diff --git a/master/buildbot/test/integration/test_upgrade.py b/master/buildbot/test/integration/test_upgrade.py
index a6a5ce223a5..084e9824180 100644
--- a/master/buildbot/test/integration/test_upgrade.py
+++ b/master/buildbot/test/integration/test_upgrade.py
@@ -111,11 +111,13 @@ def tearDownUpgradeTest(self):
     # save subclasses the trouble of calling our setUp and tearDown methods
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setUpUpgradeTest()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownUpgradeTest()
+        yield self.tearDownUpgradeTest()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def assertModelMatches(self):
diff --git a/master/buildbot/test/integration/worker/test_comm.py b/master/buildbot/test/integration/worker/test_comm.py
index 217224df007..d812ce452d5 100644
--- a/master/buildbot/test/integration/worker/test_comm.py
+++ b/master/buildbot/test/integration/worker/test_comm.py
@@ -161,7 +161,7 @@ class TestWorkerComm(unittest.TestCase, TestReactorMixin):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantData=True, wantDb=True)
 
         # set the worker port to a loopback address with unspecified
@@ -195,6 +195,7 @@ def setUp(self):
         self.server_connection_string = "tcp:0:interface=127.0.0.1"
         self.client_connection_string_tpl = "tcp:host=127.0.0.1:port={port}"
 
+    @defer.inlineCallbacks
     def tearDown(self):
         if self.broker:
             del self.broker
@@ -211,7 +212,8 @@ def tearDown(self):
         if self.buildworker and self.buildworker.detach_d:
             deferreds.append(self.buildworker.detach_d)
 
-        return defer.gatherResults(deferreds)
+        yield defer.gatherResults(deferreds)
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def addWorker(self, **kwargs):
diff --git a/master/buildbot/test/integration/worker/test_workerside.py b/master/buildbot/test/integration/worker/test_workerside.py
index 24b7f88dfe8..052a5b3f096 100644
--- a/master/buildbot/test/integration/worker/test_workerside.py
+++ b/master/buildbot/test/integration/worker/test_workerside.py
@@ -111,7 +111,7 @@ class TestWorkerConnection(unittest.TestCase, TestReactorMixin):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantData=True, wantDb=True)
         # set the worker port to a loopback address with unspecified
         # port
@@ -154,6 +154,7 @@ def tearDown(self):
         # if the worker is still attached, wait for it to detach, too
         if self.buildworker:
             yield self.buildworker.waitForCompleteShutdown()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def addMasterSideWorker(
diff --git a/master/buildbot/test/reactor.py b/master/buildbot/test/reactor.py
index e303d582ace..07b52f77551 100644
--- a/master/buildbot/test/reactor.py
+++ b/master/buildbot/test/reactor.py
@@ -15,6 +15,7 @@
 
 import asyncio
 
+from twisted.internet import defer
 from twisted.internet import threads
 from twisted.python import threadpool
 
@@ -30,7 +31,7 @@ class TestReactorMixin:
     at the end
     """
 
-    def setup_test_reactor(self, use_asyncio=False):
+    def setup_test_reactor(self, use_asyncio=False, auto_tear_down=True):
         self.patch(threadpool, 'ThreadPool', NonThreadPool)
         self.reactor = TestReactor()
         self.reactor.set_test_case(self)
@@ -44,21 +45,32 @@ def deferToThread(f, *args, **kwargs):
 
         self.patch(threads, 'deferToThread', deferToThread)
 
-        # During shutdown sequence we must first stop the reactor and only then
-        # set unset the reactor used for eventually() because any callbacks
-        # that are run during reactor.stop() may use eventually() themselves.
-        self.addCleanup(_setReactor, None)
-        self.addCleanup(self.reactor.assert_no_remaining_calls)
-        self.addCleanup(self.reactor.stop)
-
+        self._reactor_use_asyncio = use_asyncio
         if use_asyncio:
             self.asyncio_loop = AsyncIOLoopWithTwisted(self.reactor)
             asyncio.set_event_loop(self.asyncio_loop)
             self.asyncio_loop.start()
 
-            def stop():
-                self.asyncio_loop.stop()
-                self.asyncio_loop.close()
-                asyncio.set_event_loop(None)
+        if auto_tear_down:
+            self.addCleanup(self.tear_down_test_reactor)
+        self._reactor_tear_down_called = False
+
+    def tear_down_test_reactor(self):
+        if self._reactor_tear_down_called:
+            return
+
+        self._reactor_tear_down_called = True
+
+        if self._reactor_use_asyncio:
+            self.asyncio_loop.stop()
+            self.asyncio_loop.close()
+            asyncio.set_event_loop(None)
+
+        # During shutdown sequence we must first stop the reactor and only then set unset the
+        # reactor used for eventually() because any callbacks that are run during reactor.stop()
+        # may use eventually() themselves.
+        self.reactor.stop()
+        self.reactor.assert_no_remaining_calls()
+        _setReactor(None)
 
-            self.addCleanup(stop)
+        return defer.succeed(None)
diff --git a/master/buildbot/test/unit/changes/test_base.py b/master/buildbot/test/unit/changes/test_base.py
index 9aa7935c299..e5d1b74ac9e 100644
--- a/master/buildbot/test/unit/changes/test_base.py
+++ b/master/buildbot/test/unit/changes/test_base.py
@@ -32,11 +32,13 @@ class Subclass(base.ChangeSource):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpChangeSource()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownChangeSource()
+        yield self.tearDownChangeSource()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_activation(self):
@@ -82,14 +84,16 @@ class Subclass(base.ReconfigurablePollingChangeSource):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         yield self.setUpChangeSource()
 
         yield self.attachChangeSource(self.Subclass(name="DummyCS"))
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownChangeSource()
+        yield self.tearDownChangeSource()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def runClockFor(self, secs):
diff --git a/master/buildbot/test/unit/changes/test_bitbucket.py b/master/buildbot/test/unit/changes/test_bitbucket.py
index 225f5ea4e6c..18c7f37ead4 100644
--- a/master/buildbot/test/unit/changes/test_bitbucket.py
+++ b/master/buildbot/test/unit/changes/test_bitbucket.py
@@ -274,7 +274,7 @@ class TestBitbucketPullrequestPoller(
     changesource.ChangeSourceMixin, TestReactorMixin, LoggingMixin, unittest.TestCase
 ):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setUpLogging()
 
         # create pull requests
@@ -304,8 +304,10 @@ def setUp(self):
 
         return self.setUpChangeSource()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownChangeSource()
+        yield self.tearDownChangeSource()
+        yield self.tear_down_test_reactor()
 
     def _fakeGetPage(self, result):
         # Install a fake getPage that puts the requested URL in self.getPage_got_url
diff --git a/master/buildbot/test/unit/changes/test_changes.py b/master/buildbot/test/unit/changes/test_changes.py
index 067583a7386..eb86c77cc94 100644
--- a/master/buildbot/test/unit/changes/test_changes.py
+++ b/master/buildbot/test/unit/changes/test_changes.py
@@ -52,7 +52,7 @@ class Change(unittest.TestCase, TestReactorMixin):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantDb=True)
         self.change23 = changes.Change(**{  # using **dict(..) forces kwargs
             "category": 'devel',
@@ -105,6 +105,10 @@ def setUp(self):
         })
         self.change25.number = 25
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_fromChdict(self):
         # get a real honest-to-goodness chdict from the fake db
diff --git a/master/buildbot/test/unit/changes/test_gerritchangesource.py b/master/buildbot/test/unit/changes/test_gerritchangesource.py
index d086b80f3cc..28c61beee4f 100644
--- a/master/buildbot/test/unit/changes/test_gerritchangesource.py
+++ b/master/buildbot/test/unit/changes/test_gerritchangesource.py
@@ -98,7 +98,7 @@ class TestGerritChangeSource(
     unittest.TestCase,
 ):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_master_run_process()
         self._got_events = []
         return self.setUpChangeSource()
@@ -108,6 +108,7 @@ def tearDown(self):
         if self.master.running:
             yield self.master.stopService()
         yield self.tearDownChangeSource()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def create_gerrit(self, host, user, *args, **kwargs):
@@ -1046,7 +1047,7 @@ class TestGerritEventLogPoller(
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpChangeSource()
         yield self.master.startService()
 
@@ -1054,6 +1055,7 @@ def setUp(self):
     def tearDown(self):
         yield self.master.stopService()
         yield self.tearDownChangeSource()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def newChangeSource(self, **kwargs):
diff --git a/master/buildbot/test/unit/changes/test_github.py b/master/buildbot/test/unit/changes/test_github.py
index 5a9b156ba0d..7198f3fa514 100644
--- a/master/buildbot/test/unit/changes/test_github.py
+++ b/master/buildbot/test/unit/changes/test_github.py
@@ -180,7 +180,7 @@ class TestGitHubPullrequestPoller(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpChangeSource()
 
         fake_storage_service = FakeSecretStorage()
@@ -197,6 +197,7 @@ def setUp(self):
     def tearDown(self):
         yield self.master.stopService()
         yield self.tearDownChangeSource()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def newChangeSource(self, owner, repo, endpoint='https://api.github.com', **kwargs):
diff --git a/master/buildbot/test/unit/changes/test_gitpoller.py b/master/buildbot/test/unit/changes/test_gitpoller.py
index 8e7511b1715..bdab6d1b1ed 100644
--- a/master/buildbot/test/unit/changes/test_gitpoller.py
+++ b/master/buildbot/test/unit/changes/test_gitpoller.py
@@ -66,7 +66,7 @@ def createPoller(self):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_master_run_process()
         yield self.setUpChangeSource()
         yield self.master.startService()
@@ -77,6 +77,7 @@ def setUp(self):
     def tearDown(self):
         yield self.master.stopService()
         yield self.tearDownChangeSource()
+        yield self.tear_down_test_reactor()
 
     @async_to_deferred
     async def set_last_rev(self, state: dict[str, str]) -> None:
@@ -2433,7 +2434,7 @@ class TestGitPollerConstructor(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpChangeSource()
         yield self.master.startService()
 
@@ -2441,6 +2442,7 @@ def setUp(self):
     def tearDown(self):
         yield self.master.stopService()
         yield self.tearDownChangeSource()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_deprecatedFetchRefspec(self):
diff --git a/master/buildbot/test/unit/changes/test_hgpoller.py b/master/buildbot/test/unit/changes/test_hgpoller.py
index d602a168015..341c41e2526 100644
--- a/master/buildbot/test/unit/changes/test_hgpoller.py
+++ b/master/buildbot/test/unit/changes/test_hgpoller.py
@@ -39,7 +39,7 @@ class TestHgPollerBase(
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_master_run_process()
         yield self.setUpChangeSource()
 
@@ -71,6 +71,7 @@ def _isRepositoryReady():
     def tearDown(self):
         yield self.master.stopService()
         yield self.tearDownChangeSource()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def check_current_rev(self, wished, branch='default'):
diff --git a/master/buildbot/test/unit/changes/test_mail.py b/master/buildbot/test/unit/changes/test_mail.py
index 3748de6e3f0..ee8788795ab 100644
--- a/master/buildbot/test/unit/changes/test_mail.py
+++ b/master/buildbot/test/unit/changes/test_mail.py
@@ -29,7 +29,7 @@ class TestMaildirSource(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.maildir = os.path.abspath("maildir")
 
         yield self.setUpChangeSource()
@@ -56,6 +56,7 @@ def assertMailProcessed(self):
     def tearDown(self):
         yield self.tearDownDirs()
         yield self.tearDownChangeSource()
+        yield self.tear_down_test_reactor()
 
     # tests
 
diff --git a/master/buildbot/test/unit/changes/test_manager.py b/master/buildbot/test/unit/changes/test_manager.py
index 5eb1d98536f..2e63de2bc00 100644
--- a/master/buildbot/test/unit/changes/test_manager.py
+++ b/master/buildbot/test/unit/changes/test_manager.py
@@ -28,15 +28,17 @@
 class TestChangeManager(unittest.TestCase, TestReactorMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantData=True)
         self.cm = manager.ChangeManager()
         self.master.startService()
         yield self.cm.setServiceParent(self.master)
         self.new_config = mock.Mock()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.master.stopService()
+        yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     def make_sources(self, n, klass=base.ChangeSource, **kwargs):
         for i in range(n):
diff --git a/master/buildbot/test/unit/changes/test_p4poller.py b/master/buildbot/test/unit/changes/test_p4poller.py
index 929199ef7e0..a75c5d2c919 100644
--- a/master/buildbot/test/unit/changes/test_p4poller.py
+++ b/master/buildbot/test/unit/changes/test_p4poller.py
@@ -109,12 +109,14 @@ class TestP4Poller(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_master_run_process()
         yield self.setUpChangeSource()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownChangeSource()
+        yield self.tearDownChangeSource()
+        yield self.tear_down_test_reactor()
 
     def add_p4_describe_result(self, number, result):
         self.expect_commands(
diff --git a/master/buildbot/test/unit/changes/test_pb.py b/master/buildbot/test/unit/changes/test_pb.py
index 17a190210ba..4d189442be0 100644
--- a/master/buildbot/test/unit/changes/test_pb.py
+++ b/master/buildbot/test/unit/changes/test_pb.py
@@ -40,12 +40,17 @@ class TestPBChangeSource(
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setUpPBChangeSource()
         yield self.setUpChangeSource()
 
         self.master.pbmanager = self.pbmanager
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tearDownChangeSource()
+        yield self.tear_down_test_reactor()
+
     def test_registration_no_workerport(self):
         return self._test_registration(None, exp_ConfigErrors=True, user='alice', passwd='sekrit')
 
@@ -212,9 +217,13 @@ def test_reconfigService_default_changed_but_inactive(self):
 class TestChangePerspective(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantDb=True, wantData=True)
 
+        @defer.inlineCallbacks
+        def tearDown(self):
+            yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_addChange_noprefix(self):
         cp = pb.ChangePerspective(self.master, None)
diff --git a/master/buildbot/test/unit/changes/test_svnpoller.py b/master/buildbot/test/unit/changes/test_svnpoller.py
index 112439a558a..cfab8c03a5c 100644
--- a/master/buildbot/test/unit/changes/test_svnpoller.py
+++ b/master/buildbot/test/unit/changes/test_svnpoller.py
@@ -259,12 +259,14 @@ class TestSVNPoller(
     MasterRunProcessMixin, changesource.ChangeSourceMixin, TestReactorMixin, unittest.TestCase
 ):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_master_run_process()
         return self.setUpChangeSource()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownChangeSource()
+        yield self.tearDownChangeSource()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def attachSVNPoller(self, *args, **kwargs):
diff --git a/master/buildbot/test/unit/data/test_base.py b/master/buildbot/test/unit/data/test_base.py
index 16383421ebe..1829f3de3a7 100644
--- a/master/buildbot/test/unit/data/test_base.py
+++ b/master/buildbot/test/unit/data/test_base.py
@@ -26,7 +26,11 @@
 
 class ResourceType(TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
+
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
 
     def makeResourceTypeSubclass(self, **attributes):
         attributes.setdefault('name', 'thing')
diff --git a/master/buildbot/test/unit/data/test_build_data.py b/master/buildbot/test/unit/data/test_build_data.py
index af3afc4fa94..d78c056e4bc 100644
--- a/master/buildbot/test/unit/data/test_build_data.py
+++ b/master/buildbot/test/unit/data/test_build_data.py
@@ -332,10 +332,14 @@ def test_get_builds_id(self, name, buildid, exp_names):
 class TestBuildData(TestReactorMixin, interfaces.InterfaceTests, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.rtype = build_data.BuildData(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_signature_set_build_data(self):
         @self.assertArgSpecMatches(self.master.data.updates.setBuildData, self.rtype.setBuildData)
         def setBuildData(self, buildid, name, value, source):
diff --git a/master/buildbot/test/unit/data/test_builders.py b/master/buildbot/test/unit/data/test_builders.py
index bb9fc17e1b0..22799611000 100644
--- a/master/buildbot/test/unit/data/test_builders.py
+++ b/master/buildbot/test/unit/data/test_builders.py
@@ -221,7 +221,7 @@ def test_get_contains_two_tags_one_unknown(self):
 class Builder(interfaces.InterfaceTests, TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.rtype = builders.Builder(self.master)
         yield self.master.db.insert_test_data([
@@ -229,6 +229,10 @@ def setUp(self):
             fakedb.Master(id=14),
         ])
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_signature_findBuilderId(self):
         @self.assertArgSpecMatches(
             self.master.data.updates.findBuilderId,  # fake
diff --git a/master/buildbot/test/unit/data/test_buildrequests.py b/master/buildbot/test/unit/data/test_buildrequests.py
index 2c139b593c0..05b37e7c0ef 100644
--- a/master/buildbot/test/unit/data/test_buildrequests.py
+++ b/master/buildbot/test/unit/data/test_buildrequests.py
@@ -276,10 +276,14 @@ class dBLayerException(Exception):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.rtype = buildrequests.BuildRequest(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def doTestCallthrough(
         self,
diff --git a/master/buildbot/test/unit/data/test_builds.py b/master/buildbot/test/unit/data/test_builds.py
index f40fed9d8c3..e4fc75e0837 100644
--- a/master/buildbot/test/unit/data/test_builds.py
+++ b/master/buildbot/test/unit/data/test_builds.py
@@ -340,10 +340,14 @@ class Build(interfaces.InterfaceTests, TestReactorMixin, unittest.TestCase):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.rtype = builds.Build(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def do_test_callthrough(
         self,
diff --git a/master/buildbot/test/unit/data/test_buildsets.py b/master/buildbot/test/unit/data/test_buildsets.py
index 1a7517c811d..d36f2a5cd0a 100644
--- a/master/buildbot/test/unit/data/test_buildsets.py
+++ b/master/buildbot/test/unit/data/test_buildsets.py
@@ -126,7 +126,7 @@ def test_get_incomplete(self):
 class Buildset(TestReactorMixin, util_interfaces.InterfaceTests, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.rtype = buildsets.Buildset(self.master)
         yield self.master.db.insert_test_data([
@@ -143,6 +143,10 @@ def setUp(self):
             fakedb.Builder(id=43, name='bldr2'),
         ])
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     SS234_DATA = {
         'branch': 'br',
         'codebase': 'cb',
diff --git a/master/buildbot/test/unit/data/test_changes.py b/master/buildbot/test/unit/data/test_changes.py
index 83ad7f4cefa..6943256bd40 100644
--- a/master/buildbot/test/unit/data/test_changes.py
+++ b/master/buildbot/test/unit/data/test_changes.py
@@ -194,10 +194,14 @@ class Change(TestReactorMixin, interfaces.InterfaceTests, unittest.TestCase):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.rtype = changes.Change(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_signature_addChange(self):
         @self.assertArgSpecMatches(
             self.master.data.updates.addChange,  # fake
diff --git a/master/buildbot/test/unit/data/test_changesources.py b/master/buildbot/test/unit/data/test_changesources.py
index fe1167df958..5ecb0eb0cf4 100644
--- a/master/buildbot/test/unit/data/test_changesources.py
+++ b/master/buildbot/test/unit/data/test_changesources.py
@@ -148,10 +148,14 @@ def test_get_masterid_missing(self):
 class ChangeSource(TestReactorMixin, interfaces.InterfaceTests, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.rtype = changesources.ChangeSource(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_signature_findChangeSourceId(self):
         @self.assertArgSpecMatches(
             self.master.data.updates.findChangeSourceId,  # fake
diff --git a/master/buildbot/test/unit/data/test_connector.py b/master/buildbot/test/unit/data/test_connector.py
index f746021ca01..169ddb604c9 100644
--- a/master/buildbot/test/unit/data/test_connector.py
+++ b/master/buildbot/test/unit/data/test_connector.py
@@ -112,32 +112,44 @@ def updateBuilderList(self, masterid, builderNames):
 class TestFakeData(TestReactorMixin, unittest.TestCase, Tests):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantData=True, wantDb=True)
         self.data = self.master.data
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
 
 class TestDataConnector(TestReactorMixin, unittest.TestCase, Tests):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True)
         self.data = connector.DataConnector()
         yield self.data.setServiceParent(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
 
 class DataConnector(TestReactorMixin, unittest.TestCase):
     maxDiff = None
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         # don't load by default
         self.patch(connector.DataConnector, 'submodules', [])
         self.data = connector.DataConnector()
         yield self.data.setServiceParent(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def patchFooPattern(self):
         cls = type('FooEndpoint', (base.Endpoint,), {})
         ep = cls(None, self.master)
diff --git a/master/buildbot/test/unit/data/test_logs.py b/master/buildbot/test/unit/data/test_logs.py
index cd72286345c..7d73853a369 100644
--- a/master/buildbot/test/unit/data/test_logs.py
+++ b/master/buildbot/test/unit/data/test_logs.py
@@ -200,10 +200,14 @@ def test_get_builder_build_number_step_number(self):
 class Log(TestReactorMixin, interfaces.InterfaceTests, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.rtype = logs.Log(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def do_test_callthrough(
         self, dbMethodName, method, exp_args=None, exp_kwargs=None, *args, **kwargs
diff --git a/master/buildbot/test/unit/data/test_masters.py b/master/buildbot/test/unit/data/test_masters.py
index c3cd50d7256..1a98b635173 100644
--- a/master/buildbot/test/unit/data/test_masters.py
+++ b/master/buildbot/test/unit/data/test_masters.py
@@ -131,10 +131,14 @@ def test_get_builderid_missing(self):
 class Master(TestReactorMixin, interfaces.InterfaceTests, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.rtype = masters.Master(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_signature_masterActive(self):
         @self.assertArgSpecMatches(
             self.master.data.updates.masterActive,  # fake
diff --git a/master/buildbot/test/unit/data/test_patches.py b/master/buildbot/test/unit/data/test_patches.py
index eeb184aadc4..a1db26744cf 100644
--- a/master/buildbot/test/unit/data/test_patches.py
+++ b/master/buildbot/test/unit/data/test_patches.py
@@ -24,8 +24,12 @@
 class Patch(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.rtype = patches.Patch(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     # no update methods -> nothing to test
diff --git a/master/buildbot/test/unit/data/test_projects.py b/master/buildbot/test/unit/data/test_projects.py
index c991afb6232..9f6ae11717b 100644
--- a/master/buildbot/test/unit/data/test_projects.py
+++ b/master/buildbot/test/unit/data/test_projects.py
@@ -115,13 +115,17 @@ def test_get(self, name, active_filter, expected_projectids):
 class Project(interfaces.InterfaceTests, TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.rtype = projects.Project(self.master)
         yield self.master.db.insert_test_data([
             fakedb.Project(id=13, name="fake_project"),
         ])
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_signature_find_project_id(self):
         @self.assertArgSpecMatches(
             self.master.data.updates.find_project_id,  # fake
diff --git a/master/buildbot/test/unit/data/test_properties.py b/master/buildbot/test/unit/data/test_properties.py
index 5a9a96b62f4..c99f1c25bac 100644
--- a/master/buildbot/test/unit/data/test_properties.py
+++ b/master/buildbot/test/unit/data/test_properties.py
@@ -91,10 +91,14 @@ def test_get_properties_from_builder(self):
 class Properties(interfaces.InterfaceTests, TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=False, wantDb=True, wantData=True)
         self.rtype = properties.Properties(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def do_test_callthrough(
         self, dbMethodName, method, exp_args=None, exp_kwargs=None, *args, **kwargs
diff --git a/master/buildbot/test/unit/data/test_schedulers.py b/master/buildbot/test/unit/data/test_schedulers.py
index c94b9db3452..b1d637acd37 100644
--- a/master/buildbot/test/unit/data/test_schedulers.py
+++ b/master/buildbot/test/unit/data/test_schedulers.py
@@ -145,10 +145,14 @@ def test_get_masterid_missing(self):
 class Scheduler(TestReactorMixin, interfaces.InterfaceTests, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.rtype = schedulers.Scheduler(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_signature_schedulerEnable(self):
         @self.assertArgSpecMatches(
             self.master.data.updates.schedulerEnable, self.rtype.schedulerEnable
diff --git a/master/buildbot/test/unit/data/test_steps.py b/master/buildbot/test/unit/data/test_steps.py
index bc5dae13f8b..17725abdcea 100644
--- a/master/buildbot/test/unit/data/test_steps.py
+++ b/master/buildbot/test/unit/data/test_steps.py
@@ -217,10 +217,14 @@ def test_get_buildername(self):
 class Step(TestReactorMixin, interfaces.InterfaceTests, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.rtype = steps.Step(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_signature_addStep(self):
         @self.assertArgSpecMatches(
             self.master.data.updates.addStep,  # fake
diff --git a/master/buildbot/test/unit/data/test_test_result_sets.py b/master/buildbot/test/unit/data/test_test_result_sets.py
index f52409b9532..84c0058f905 100644
--- a/master/buildbot/test/unit/data/test_test_result_sets.py
+++ b/master/buildbot/test/unit/data/test_test_result_sets.py
@@ -158,10 +158,14 @@ def test_get_result_sets_steps_stepid(self):
 class TestResultSet(TestReactorMixin, interfaces.InterfaceTests, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.rtype = test_result_sets.TestResultSet(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_signature_add_test_result_set(self):
         @self.assertArgSpecMatches(
             self.master.data.updates.addTestResultSet, self.rtype.addTestResultSet
diff --git a/master/buildbot/test/unit/data/test_test_results.py b/master/buildbot/test/unit/data/test_test_results.py
index 1ff5ed355c7..29e5ef05f1f 100644
--- a/master/buildbot/test/unit/data/test_test_results.py
+++ b/master/buildbot/test/unit/data/test_test_results.py
@@ -98,10 +98,14 @@ def test_get_missing_results(self):
 class TestResult(TestReactorMixin, interfaces.InterfaceTests, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.rtype = test_results.TestResult(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_signature_add_test_results(self):
         @self.assertArgSpecMatches(
             self.master.data.updates.addTestResults, self.rtype.addTestResults
diff --git a/master/buildbot/test/unit/data/test_workers.py b/master/buildbot/test/unit/data/test_workers.py
index 1c6500bdf6f..cd100cbb82e 100644
--- a/master/buildbot/test/unit/data/test_workers.py
+++ b/master/buildbot/test/unit/data/test_workers.py
@@ -294,7 +294,7 @@ def test_set_worker_paused_find_by_paused(self):
 class Worker(TestReactorMixin, interfaces.InterfaceTests, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.rtype = workers.Worker(self.master)
         yield self.master.db.insert_test_data([
@@ -302,6 +302,10 @@ def setUp(self):
             fakedb.Master(id=14),
         ])
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_signature_findWorkerId(self):
         @self.assertArgSpecMatches(
             self.master.data.updates.findWorkerId,  # fake
diff --git a/master/buildbot/test/unit/db/test_connector.py b/master/buildbot/test/unit/db/test_connector.py
index b02f3d17078..eea63b334af 100644
--- a/master/buildbot/test/unit/db/test_connector.py
+++ b/master/buildbot/test/unit/db/test_connector.py
@@ -34,7 +34,7 @@ class TestDBConnector(TestReactorMixin, db.RealDatabaseMixin, unittest.TestCase)
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpRealDatabase(
             table_names=[
                 'changes',
@@ -65,6 +65,7 @@ def tearDown(self):
             yield self.db.stopService()
 
         yield self.tearDownRealDatabase()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def startService(self, check_version=False):
diff --git a/master/buildbot/test/unit/process/test_botmaster_BotMaster.py b/master/buildbot/test/unit/process/test_botmaster_BotMaster.py
index 9a8d1ca1b6b..7da0f15c8bd 100644
--- a/master/buildbot/test/unit/process/test_botmaster_BotMaster.py
+++ b/master/buildbot/test/unit/process/test_botmaster_BotMaster.py
@@ -30,12 +30,16 @@
 class TestCleanShutdown(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantData=True)
         self.botmaster = BotMaster()
         yield self.botmaster.setServiceParent(self.master)
         self.botmaster.startService()
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def assertReactorStopped(self, _=None):
         self.assertTrue(self.reactor.stop_called)
 
@@ -152,7 +156,7 @@ def test_shutdown_cancel(self):
 class TestBotMaster(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantData=True)
         self.master.mq = self.master.mq
         self.master.botmaster.disownServiceParent()
@@ -161,8 +165,10 @@ def setUp(self):
         self.new_config = mock.Mock()
         self.botmaster.startService()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.botmaster.stopService()
+        yield self.botmaster.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_reconfigServiceWithBuildbotConfig(self):
diff --git a/master/buildbot/test/unit/process/test_build.py b/master/buildbot/test/unit/process/test_build.py
index dfcfd6c4f22..e9412ec8ea8 100644
--- a/master/buildbot/test/unit/process/test_build.py
+++ b/master/buildbot/test/unit/process/test_build.py
@@ -180,7 +180,7 @@ def makeControllableStepFactory():
 class TestBuild(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         r = FakeRequest()
         r.sources = [FakeSource()]
         r.sources[0].changes = [FakeChange()]
@@ -205,6 +205,10 @@ def setUp(self):
         self.build.text = []
         self.build.buildid = 666
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def assertWorkerPreparationFailure(self, reason):
         states = "".join(self.master.data.updates.stepStateString.values())
         self.assertIn(states, reason)
@@ -887,7 +891,7 @@ def get_active_builds():
 class TestMultipleSourceStamps(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         self.builder = FakeBuilder(self.master)
 
@@ -911,6 +915,10 @@ def setUp(self):
 
         self.build = Build([r], self.builder)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_buildReturnSourceStamp(self):
         """
         Test that a build returns the correct sourcestamp
@@ -934,7 +942,7 @@ def test_buildReturnSourceStamp_empty_codebase(self):
 class TestBuildBlameList(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         self.builder = FakeBuilder(self.master)
 
@@ -959,6 +967,10 @@ def setUp(self):
         self.patchSource.revision = "67890"
         self.patchSource.patch_info = ("jeff", "jeff's new feature")
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_blamelist_for_changes(self):
         r = FakeRequest()
         r.sources.extend([self.sourceByMe, self.sourceByHim])
@@ -983,7 +995,7 @@ class TestSetupProperties_MultipleSources(TestReactorMixin, unittest.TestCase):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.props = {}
         self.r = FakeRequest()
         self.r.sources = []
@@ -1004,6 +1016,10 @@ def setUp(self):
         # record properties that will be set
         self.build.properties.setProperty = self.setProperty
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def setProperty(self, n, v, s, runtime=False):
         if s not in self.props:
             self.props[s] = {}
@@ -1028,7 +1044,7 @@ class TestSetupProperties_SingleSource(TestReactorMixin, unittest.TestCase):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.props = {}
         self.r = FakeRequest()
         self.r.sources = []
@@ -1044,6 +1060,10 @@ def setUp(self):
         # record properties that will be set
         self.build.properties.setProperty = self.setProperty
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def setProperty(self, n, v, s, runtime=False):
         if s not in self.props:
             self.props[s] = {}
diff --git a/master/buildbot/test/unit/process/test_builder.py b/master/buildbot/test/unit/process/test_builder.py
index a0e7c5b08f6..ac50ade4fb9 100644
--- a/master/buildbot/test/unit/process/test_builder.py
+++ b/master/buildbot/test/unit/process/test_builder.py
@@ -108,7 +108,7 @@ def reconfigService(self, name, _, **kwargs):
 class TestBuilder(TestReactorMixin, BuilderMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         # a collection of rows that would otherwise clutter up every test
         yield self.setUpBuilderMixin()
         self.base_rows = [
@@ -117,6 +117,10 @@ def setUp(self):
             fakedb.BuildsetSourceStamp(buildsetid=11, sourcestampid=21),
         ]
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def makeBuilder(self, patch_random=False, startBuildsForSucceeds=True, **config_kwargs):
         yield super().makeBuilder(patch_random=patch_random, **config_kwargs)
@@ -480,9 +484,13 @@ def test_defaultProperties(self):
 class TestGetBuilderId(TestReactorMixin, BuilderMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpBuilderMixin()
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_getBuilderId(self):
         # noReconfig because reconfigService calls getBuilderId, and we haven't
@@ -503,7 +511,7 @@ def test_getBuilderId(self):
 class TestGetOldestRequestTime(TestReactorMixin, BuilderMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpBuilderMixin()
 
         # a collection of rows that would otherwise clutter up every test
@@ -525,6 +533,10 @@ def setUp(self):
         ]
         yield self.db.insert_test_data(self.base_rows)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_gort_unclaimed(self):
         yield self.makeBuilder(name='bldr1')
@@ -548,7 +560,7 @@ def test_gort_all_claimed(self):
 class TestGetNewestCompleteTime(TestReactorMixin, BuilderMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpBuilderMixin()
 
         # a collection of rows that would otherwise clutter up every test
@@ -573,6 +585,10 @@ def setUp(self):
         ]
         yield self.db.insert_test_data(self.base_rows)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_gnct_completed(self):
         yield self.makeBuilder(name='bldr1')
@@ -589,7 +605,7 @@ def test_gnct_no_completed(self):
 class TestGetHighestPriority(TestReactorMixin, BuilderMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpBuilderMixin()
 
         # a collection of rows that would otherwise clutter up every test
@@ -612,6 +628,10 @@ def setUp(self):
         ]
         yield self.db.insert_test_data(self.base_rows)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_ghp_unclaimed(self):
         yield self.makeBuilder(name='bldr1')
@@ -630,7 +650,7 @@ class TestReconfig(TestReactorMixin, BuilderMixin, unittest.TestCase):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpBuilderMixin()
 
         yield self.db.insert_test_data([
@@ -638,6 +658,10 @@ def setUp(self):
             fakedb.Project(id=302, name='new_project'),
         ])
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_reconfig(self):
         yield self.makeBuilder(description="Old", project="old_project", tags=["OldTag"])
diff --git a/master/buildbot/test/unit/process/test_buildrequest.py b/master/buildbot/test/unit/process/test_buildrequest.py
index ec221ec4233..fae666f3ef3 100644
--- a/master/buildbot/test/unit/process/test_buildrequest.py
+++ b/master/buildbot/test/unit/process/test_buildrequest.py
@@ -30,7 +30,7 @@
 class TestBuildRequestCollapser(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True)
         self.master.botmaster = mock.Mock(name='botmaster')
         self.master.botmaster.builders = {}
@@ -53,8 +53,9 @@ def createBuilder(self, name, builderid=None):
 
         return bldr
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        pass
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def do_request_collapse(self, rows, brids, exp):
@@ -461,7 +462,11 @@ def test_asdict_with_patch(self):
 
 class TestBuildRequest(TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
+
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_fromBrdict(self):
diff --git a/master/buildbot/test/unit/process/test_buildrequestdistributor.py b/master/buildbot/test/unit/process/test_buildrequestdistributor.py
index beb2bafdad0..ad822350119 100644
--- a/master/buildbot/test/unit/process/test_buildrequestdistributor.py
+++ b/master/buildbot/test/unit/process/test_buildrequestdistributor.py
@@ -47,7 +47,7 @@ def pick_nth_by_name(builder, workers=None, br=None):
 class TestBRDBase(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.botmaster = mock.Mock(name='botmaster')
         self.botmaster.builders = {}
         self.builders = {}
@@ -73,10 +73,11 @@ def prioritizeBuilders(master, builders):
             fakedb.BuildsetSourceStamp(sourcestampid=21, buildsetid=11),
         ]
 
+    @defer.inlineCallbacks
     def tearDown(self):
         if self.brd.running:
-            return self.brd.stopService()
-        return None
+            yield self.brd.stopService()
+        yield self.tear_down_test_reactor()
 
     def make_workers(self, worker_count):
         rows = self.base_rows[:]
diff --git a/master/buildbot/test/unit/process/test_buildstep.py b/master/buildbot/test/unit/process/test_buildstep.py
index 2882273b453..a4c7055d847 100644
--- a/master/buildbot/test/unit/process/test_buildstep.py
+++ b/master/buildbot/test/unit/process/test_buildstep.py
@@ -115,11 +115,13 @@ def run(self):
             return SUCCESS
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     # support
 
@@ -1090,10 +1092,14 @@ def addLogObserver(self, logname, observer):
 class TestFakeItfc(unittest.TestCase, TestBuildStepMixin, TestReactorMixin, InterfaceTests):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setup_test_build_step()
         self.setup_step(buildstep.BuildStep())
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
 
 class TestRealItfc(unittest.TestCase, InterfaceTests):
     def setUp(self):
@@ -1114,12 +1120,14 @@ def run(self):
 class TestCommandMixin(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setup_test_build_step()
         self.setup_step(CommandMixinExample())
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_runRmdir(self):
@@ -1231,11 +1239,13 @@ class TestShellMixin(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setup_test_build_step(with_secrets={"s3cr3t": "really_safe_string"})
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_setupShellMixin_bad_arg(self):
         mixin = SimpleShellCommand()
diff --git a/master/buildbot/test/unit/process/test_debug.py b/master/buildbot/test/unit/process/test_debug.py
index 7801120849b..8bcdc01f4a6 100644
--- a/master/buildbot/test/unit/process/test_debug.py
+++ b/master/buildbot/test/unit/process/test_debug.py
@@ -32,10 +32,14 @@ class FakeManhole(service.AsyncService):
 
 class TestDebugServices(TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = mock.Mock(name='master')
         self.config = MasterConfig()
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_reconfigService_manhole(self):
         master = yield fakemaster.make_master(self)
diff --git a/master/buildbot/test/unit/process/test_log.py b/master/buildbot/test/unit/process/test_log.py
index 7ecd7d18971..7d97f048858 100644
--- a/master/buildbot/test/unit/process/test_log.py
+++ b/master/buildbot/test/unit/process/test_log.py
@@ -29,9 +29,13 @@
 class Tests(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantData=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def makeLog(self, type, logEncoding='utf-8'):
         logid = yield self.master.data.updates.addLog(stepid=27, name='testlog', type=str(type))
diff --git a/master/buildbot/test/unit/process/test_logobserver.py b/master/buildbot/test/unit/process/test_logobserver.py
index cb61012606c..2097b3be79f 100644
--- a/master/buildbot/test/unit/process/test_logobserver.py
+++ b/master/buildbot/test/unit/process/test_logobserver.py
@@ -45,9 +45,13 @@ def finishReceived(self):
 class TestLogObserver(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantData=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_sequence(self):
         logid = yield self.master.data.updates.addLog(1, 'mine', 's')
@@ -96,9 +100,13 @@ def finishReceived(self):
 class TestLineConsumerLogObesrver(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantData=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def do_test_sequence(self, consumer):
         logid = yield self.master.data.updates.addLog(1, 'mine', 's')
@@ -169,9 +177,13 @@ def consumer():
 class TestLogLineObserver(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantData=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_sequence(self):
         logid = yield self.master.data.updates.addLog(1, 'mine', 's')
@@ -209,9 +221,13 @@ def test_old_setMaxLineLength(self):
 class TestOutputProgressObserver(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantData=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_sequence(self):
         logid = yield self.master.data.updates.addLog(1, 'mine', 's')
@@ -229,9 +245,13 @@ def test_sequence(self):
 class TestBufferObserver(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantData=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def do_test_sequence(self, lo):
         logid = yield self.master.data.updates.addLog(1, 'mine', 's')
diff --git a/master/buildbot/test/unit/process/test_metrics.py b/master/buildbot/test/unit/process/test_metrics.py
index 0fca487b5dd..bc976af1dc2 100644
--- a/master/buildbot/test/unit/process/test_metrics.py
+++ b/master/buildbot/test/unit/process/test_metrics.py
@@ -28,7 +28,7 @@
 class TestMetricBase(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.observer = metrics.MetricLogObserver()
         self.observer.parent = self.master = yield fakemaster.make_master(self)
         self.master.config.metrics = {"log_interval": 0, "periodic_interval": 0}
@@ -36,9 +36,11 @@ def setUp(self):
         self.observer.startService()
         self.observer.reconfigServiceWithBuildbotConfig(self.master.config)
 
+    @defer.inlineCallbacks
     def tearDown(self):
         if self.observer.running:
-            self.observer.stopService()
+            yield self.observer.stopService()
+        yield self.tear_down_test_reactor()
 
 
 class TestMetricCountEvent(TestMetricBase):
diff --git a/master/buildbot/test/unit/process/test_users_manual.py b/master/buildbot/test/unit/process/test_users_manual.py
index 024dd933bed..25fd041421a 100644
--- a/master/buildbot/test/unit/process/test_users_manual.py
+++ b/master/buildbot/test/unit/process/test_users_manual.py
@@ -47,9 +47,13 @@ class TestUsersBase(unittest.TestCase):
 
 class TestCommandlineUserManagerPerspective(TestReactorMixin, unittest.TestCase, ManualUsersMixin):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setUpManualUsers()
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def call_perspective_commandline(self, *args):
         persp = manual.CommandlineUserManagerPerspective(self.master)
         return persp.perspective_commandline(*args)
@@ -246,13 +250,17 @@ def test_perspective_commandline_get_no_match_format(self):
 class TestCommandlineUserManager(TestReactorMixin, unittest.TestCase, ManualUsersMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setUpManualUsers()
         self.manual_component = manual.CommandlineUserManager(
             username="user", passwd="userpw", port="9990"
         )
         yield self.manual_component.setServiceParent(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_no_userpass(self):
         d = defer.maybeDeferred(manual.CommandlineUserManager)
         return self.assertFailure(d, AssertionError)
diff --git a/master/buildbot/test/unit/process/test_users_users.py b/master/buildbot/test/unit/process/test_users_users.py
index 5e987a41e1a..d73956d56d9 100644
--- a/master/buildbot/test/unit/process/test_users_users.py
+++ b/master/buildbot/test/unit/process/test_users_users.py
@@ -28,11 +28,15 @@
 class UsersTests(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantDb=True)
         self.db = self.master.db
         self.test_sha = users.encrypt("cancer")
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def verify_users(self, users):
         users_no_attrs = copy.deepcopy(users)
diff --git a/master/buildbot/test/unit/reporters/test_base.py b/master/buildbot/test/unit/reporters/test_base.py
index 046de202aef..7628954de36 100644
--- a/master/buildbot/test/unit/reporters/test_base.py
+++ b/master/buildbot/test/unit/reporters/test_base.py
@@ -40,11 +40,15 @@ class TestReporterBase(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_reporter_test()
         self.setUpLogging()
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def setupNotifier(self, generators):
         mn = ReporterBase(generators=generators)
diff --git a/master/buildbot/test/unit/reporters/test_bitbucket.py b/master/buildbot/test/unit/reporters/test_bitbucket.py
index 3e27819867a..295bfb899fd 100644
--- a/master/buildbot/test/unit/reporters/test_bitbucket.py
+++ b/master/buildbot/test/unit/reporters/test_bitbucket.py
@@ -38,7 +38,7 @@ class TestBitbucketStatusPush(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         self.setup_reporter_test()
         self.reporter_test_repo = 'https://example.org/user/repo'
@@ -62,6 +62,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.bsp.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_basic(self):
@@ -271,7 +272,7 @@ class TestBitbucketStatusPushProperties(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         self.setup_reporter_test()
         self.reporter_test_repo = 'https://example.org/user/repo'
@@ -310,6 +311,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.bsp.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_properties(self):
@@ -375,7 +377,7 @@ def test_auth_error(self):
 class TestBitbucketStatusPushRepoParsing(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
 
         self.bsp = BitbucketStatusPush(Interpolate('key'), Interpolate('secret'))
@@ -385,6 +387,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.bsp.stopService()
+        yield self.tear_down_test_reactor()
 
     def parse(self, repourl):
         return tuple(self.bsp.get_owner_and_repo(repourl))
diff --git a/master/buildbot/test/unit/reporters/test_bitbucketserver.py b/master/buildbot/test/unit/reporters/test_bitbucketserver.py
index a9a39f32031..5f4ee48b9da 100644
--- a/master/buildbot/test/unit/reporters/test_bitbucketserver.py
+++ b/master/buildbot/test/unit/reporters/test_bitbucketserver.py
@@ -54,7 +54,7 @@ class TestBitbucketServerStatusPush(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_reporter_test()
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
         yield self.master.startService()
@@ -72,6 +72,7 @@ def setupReporter(self, **kwargs):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def _check_start_and_finish_build(self, build):
@@ -219,7 +220,7 @@ class TestBitbucketServerCoreAPIStatusPush(
 ):
     @defer.inlineCallbacks
     def setupReporter(self, token=None, **kwargs):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_reporter_test()
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
 
@@ -251,8 +252,10 @@ def setUp(self):
 
     @defer.inlineCallbacks
     def tearDown(self):
-        if self.master and self.master.running:
-            yield self.master.stopService()
+        if self.master:
+            if self.master.running:
+                yield self.master.stopService()
+            yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def _check_start_and_finish_build(self, build, parentPlan=False, epoch=False):
@@ -628,7 +631,7 @@ class TestBitbucketServerPRCommentPush(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_reporter_test()
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
         yield self.master.startService()
@@ -666,6 +669,7 @@ def setupReporter(self, verbose=True, generator_class=BuildStatusGenerator, **kw
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def setupBuildResults(self, buildResults, set_pr=True):
diff --git a/master/buildbot/test/unit/reporters/test_generators_build.py b/master/buildbot/test/unit/reporters/test_generators_build.py
index 5118f39b970..c232f546c5c 100644
--- a/master/buildbot/test/unit/reporters/test_generators_build.py
+++ b/master/buildbot/test/unit/reporters/test_generators_build.py
@@ -35,10 +35,14 @@
 class TestBuildGenerator(ConfigErrorsMixin, TestReactorMixin, unittest.TestCase, ReporterTestMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_reporter_test()
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def insert_build_finished_get_props(
         self, results, add_logs=None, want_logs_content=False, **kwargs
@@ -297,10 +301,14 @@ class TestBuildStartEndGenerator(
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_reporter_test()
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def insert_build_finished_get_props(
         self, results, add_logs=None, want_logs_content=False, **kwargs
diff --git a/master/buildbot/test/unit/reporters/test_generators_buildrequest.py b/master/buildbot/test/unit/reporters/test_generators_buildrequest.py
index 6ce7f00216b..8ddc4ea260e 100644
--- a/master/buildbot/test/unit/reporters/test_generators_buildrequest.py
+++ b/master/buildbot/test/unit/reporters/test_generators_buildrequest.py
@@ -36,7 +36,7 @@ class TestBuildRequestGenerator(
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_reporter_test()
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
 
@@ -44,6 +44,10 @@ def setUp(self):
         builder.master = self.master
         self.master.botmaster.getBuilderById = Mock(return_value=builder)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @parameterized.expand([
         ('tags', 'tag'),
         ('tags', 1),
diff --git a/master/buildbot/test/unit/reporters/test_generators_buildset.py b/master/buildbot/test/unit/reporters/test_generators_buildset.py
index 0777b8dc75b..16e84f64be2 100644
--- a/master/buildbot/test/unit/reporters/test_generators_buildset.py
+++ b/master/buildbot/test/unit/reporters/test_generators_buildset.py
@@ -34,10 +34,14 @@ class TestBuildSetGeneratorBase(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_reporter_test()
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def insert_build_finished_get_props(self, results, **kwargs):
         build = yield self.insert_build_finished(results, **kwargs)
diff --git a/master/buildbot/test/unit/reporters/test_generators_utils.py b/master/buildbot/test/unit/reporters/test_generators_utils.py
index ff06b638885..29d1ff539b3 100644
--- a/master/buildbot/test/unit/reporters/test_generators_utils.py
+++ b/master/buildbot/test/unit/reporters/test_generators_utils.py
@@ -36,10 +36,14 @@
 class TestBuildGenerator(ConfigErrorsMixin, TestReactorMixin, unittest.TestCase, ReporterTestMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_reporter_test()
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def insert_build_finished_get_props(self, results, **kwargs):
         build = yield self.insert_build_finished(results, **kwargs)
diff --git a/master/buildbot/test/unit/reporters/test_generators_worker.py b/master/buildbot/test/unit/reporters/test_generators_worker.py
index d845730bddb..1431f308a88 100644
--- a/master/buildbot/test/unit/reporters/test_generators_worker.py
+++ b/master/buildbot/test/unit/reporters/test_generators_worker.py
@@ -26,9 +26,13 @@
 class TestWorkerMissingGenerator(ConfigErrorsMixin, TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def _get_worker_dict(self, worker_name):
         return {
             'name': worker_name,
diff --git a/master/buildbot/test/unit/reporters/test_gerrit.py b/master/buildbot/test/unit/reporters/test_gerrit.py
index 3589f807743..871cdf205d1 100644
--- a/master/buildbot/test/unit/reporters/test_gerrit.py
+++ b/master/buildbot/test/unit/reporters/test_gerrit.py
@@ -122,10 +122,14 @@ def sampleSummaryCBDeferred(buildInfoList, results, master, arg):
 class TestGerritStatusPush(TestReactorMixin, unittest.TestCase, ReporterTestMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_reporter_test()
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def setupGerritStatusPushSimple(self, *args, **kwargs):
         serv = kwargs.pop("server", "serv")
diff --git a/master/buildbot/test/unit/reporters/test_gerrit_verify_status.py b/master/buildbot/test/unit/reporters/test_gerrit_verify_status.py
index 346741b9bda..fe8f2ca6686 100644
--- a/master/buildbot/test/unit/reporters/test_gerrit_verify_status.py
+++ b/master/buildbot/test/unit/reporters/test_gerrit_verify_status.py
@@ -39,7 +39,7 @@ class TestGerritVerifyStatusPush(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_reporter_test()
         self.reporter_test_props = {'gerrit_changes': [{'change_id': 12, 'revision_id': 2}]}
 
@@ -57,8 +57,10 @@ def createGerritStatus(self, **kwargs):
         self.sp = GerritVerifyStatusPush("gerrit", auth=auth, **kwargs)
         yield self.sp.setServiceParent(self.master)
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.master.stopService()
+        yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_basic(self):
diff --git a/master/buildbot/test/unit/reporters/test_github.py b/master/buildbot/test/unit/reporters/test_github.py
index ad12f786f36..988fab2422b 100644
--- a/master/buildbot/test/unit/reporters/test_github.py
+++ b/master/buildbot/test/unit/reporters/test_github.py
@@ -35,7 +35,7 @@ class TestGitHubStatusPush(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         self.setup_reporter_test()
         # project must be in the form <owner>/<project>
@@ -58,8 +58,10 @@ def setUp(self):
     def createService(self):
         return GitHubStatusPush(Interpolate('XXYYZZ'))
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.master.stopService()
+        yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_basic(self):
@@ -300,7 +302,7 @@ def test_multiple_source_stamps_no_props(self):
 class TestGitHubStatusPushURL(TestReactorMixin, unittest.TestCase, ReporterTestMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         self.setup_reporter_test()
         # project must be in the form <owner>/<project>
@@ -324,8 +326,10 @@ def setUp(self):
     def createService(self):
         return GitHubStatusPush('XXYYZZ')
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.master.stopService()
+        yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_ssh(self):
diff --git a/master/buildbot/test/unit/reporters/test_gitlab.py b/master/buildbot/test/unit/reporters/test_gitlab.py
index 1847452ef89..e0df58331ea 100644
--- a/master/buildbot/test/unit/reporters/test_gitlab.py
+++ b/master/buildbot/test/unit/reporters/test_gitlab.py
@@ -38,7 +38,7 @@ class TestGitLabStatusPush(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         self.setup_reporter_test()
         # repository must be in the form http://gitlab/<owner>/<project>
@@ -68,8 +68,10 @@ def setup_properties(props):
         builder.setup_properties = setup_properties
         self.master.botmaster.getBuilderById = mock.Mock(return_value=builder)
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.master.stopService()
+        yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_buildrequest(self):
diff --git a/master/buildbot/test/unit/reporters/test_http.py b/master/buildbot/test/unit/reporters/test_http.py
index 5beed2956ac..9f6e9bc2186 100644
--- a/master/buildbot/test/unit/reporters/test_http.py
+++ b/master/buildbot/test/unit/reporters/test_http.py
@@ -30,7 +30,7 @@
 class TestHttpStatusPush(TestReactorMixin, unittest.TestCase, ReporterTestMixin, ConfigErrorsMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_reporter_test()
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
         yield self.master.startService()
@@ -53,6 +53,7 @@ def createReporter(self, auth=("username", "passwd"), headers=None, **kwargs):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_basic(self):
diff --git a/master/buildbot/test/unit/reporters/test_mail.py b/master/buildbot/test/unit/reporters/test_mail.py
index 780d1fc8405..d80fc82dabe 100644
--- a/master/buildbot/test/unit/reporters/test_mail.py
+++ b/master/buildbot/test/unit/reporters/test_mail.py
@@ -41,10 +41,14 @@
 class TestMailNotifier(ConfigErrorsMixin, TestReactorMixin, unittest.TestCase, ReporterTestMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_reporter_test()
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def setupMailNotifier(self, *args, **kwargs):
         mn = MailNotifier(*args, **kwargs)
diff --git a/master/buildbot/test/unit/reporters/test_message.py b/master/buildbot/test/unit/reporters/test_message.py
index 83400e0d04e..bd8c4820711 100644
--- a/master/buildbot/test/unit/reporters/test_message.py
+++ b/master/buildbot/test/unit/reporters/test_message.py
@@ -160,9 +160,13 @@ def test_get_message_source_stamp_text_with_props(self):
 class MessageFormatterTestBase(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def setup_db(self, results1, results2, with_steps=False, extra_build_properties=None):
         if extra_build_properties is None:
diff --git a/master/buildbot/test/unit/reporters/test_pushjet.py b/master/buildbot/test/unit/reporters/test_pushjet.py
index 556cf7a7752..fb11bf42175 100644
--- a/master/buildbot/test/unit/reporters/test_pushjet.py
+++ b/master/buildbot/test/unit/reporters/test_pushjet.py
@@ -34,9 +34,13 @@
 class TestPushjetNotifier(ConfigErrorsMixin, TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     # returns a Deferred
     def setupFakeHttp(self, base_url='https://api.pushjet.io'):
         return fakehttpclientservice.HTTPClientService.getService(self.master, self, base_url)
diff --git a/master/buildbot/test/unit/reporters/test_pushover.py b/master/buildbot/test/unit/reporters/test_pushover.py
index 09145925ead..797b396e375 100644
--- a/master/buildbot/test/unit/reporters/test_pushover.py
+++ b/master/buildbot/test/unit/reporters/test_pushover.py
@@ -34,9 +34,13 @@
 class TestPushoverNotifier(ConfigErrorsMixin, TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     # returns a Deferred
     def setupFakeHttp(self):
         return fakehttpclientservice.HTTPClientService.getService(
diff --git a/master/buildbot/test/unit/reporters/test_telegram.py b/master/buildbot/test/unit/reporters/test_telegram.py
index cddfe95fb56..5dc4a019620 100644
--- a/master/buildbot/test/unit/reporters/test_telegram.py
+++ b/master/buildbot/test/unit/reporters/test_telegram.py
@@ -554,11 +554,15 @@ class TestTelegramService(TestReactorMixin, unittest.TestCase):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.patch(reactor, 'callLater', self.reactor.callLater)
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
         self.http = None
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def setup_http_service(self):
         self.http = yield fakehttpclientservice.HTTPClientService.getService(
diff --git a/master/buildbot/test/unit/reporters/test_utils.py b/master/buildbot/test/unit/reporters/test_utils.py
index 3783d52fd44..6e3471cf6bc 100644
--- a/master/buildbot/test/unit/reporters/test_utils.py
+++ b/master/buildbot/test/unit/reporters/test_utils.py
@@ -39,9 +39,13 @@ class TestDataUtils(TestReactorMixin, unittest.TestCase, logging.LoggingMixin):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True, wantMq=True)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def setupDb(self):
         self.db = self.master.db
@@ -612,9 +616,13 @@ def test_getPreviousBuildWithRetry(self):
 class TestURLUtils(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_UrlForBuild(self):
         self.assertEqual(
             utils.getURLForBuild(self.master, 1, 3), 'http://localhost:8080/#/builders/1/builds/3'
diff --git a/master/buildbot/test/unit/reporters/test_words.py b/master/buildbot/test/unit/reporters/test_words.py
index cdda6cc6fe9..22ed43f295c 100644
--- a/master/buildbot/test/unit/reporters/test_words.py
+++ b/master/buildbot/test/unit/reporters/test_words.py
@@ -48,7 +48,7 @@ class ContactMixin(TestReactorMixin):
 
     @defer.inlineCallbacks
     def setUp(self) -> Generator[Any, None, None]:
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.patch(reactor, 'callLater', self.reactor.callLater)
         self.patch(reactor, 'seconds', self.reactor.seconds)
         self.patch(reactor, 'stop', self.reactor.stop)
@@ -88,6 +88,10 @@ def cancelCleanShutdown():
         yield self.contact.channel.setServiceParent(self.master)
         yield self.master.startService()
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def patch_send(self):
         self.sent = []
 
diff --git a/master/buildbot/test/unit/reporters/test_zulip.py b/master/buildbot/test/unit/reporters/test_zulip.py
index 3a91d5a622b..2df5270271c 100644
--- a/master/buildbot/test/unit/reporters/test_zulip.py
+++ b/master/buildbot/test/unit/reporters/test_zulip.py
@@ -30,7 +30,7 @@ class TestZulipStatusPush(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_reporter_test()
         self.master = yield fakemaster.make_master(
             testcase=self, wantData=True, wantDb=True, wantMq=True
@@ -40,6 +40,7 @@ def setUp(self):
     def tearDown(self):
         if self.master.running:
             yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def setupZulipStatusPush(self, endpoint="http://example.com", token="123", stream=None):
diff --git a/master/buildbot/test/unit/schedulers/test_base.py b/master/buildbot/test/unit/schedulers/test_base.py
index 1244185a9f2..2fc413dfa76 100644
--- a/master/buildbot/test/unit/schedulers/test_base.py
+++ b/master/buildbot/test/unit/schedulers/test_base.py
@@ -37,11 +37,13 @@ class BaseScheduler(scheduler.SchedulerMixin, TestReactorMixin, unittest.TestCas
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpScheduler()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        self.tearDownScheduler()
+        yield self.tearDownScheduler()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def makeScheduler(self, name='testsched', builderNames=None, properties=None, codebases=None):
diff --git a/master/buildbot/test/unit/schedulers/test_basic.py b/master/buildbot/test/unit/schedulers/test_basic.py
index d708b866df7..0092e2f2e86 100644
--- a/master/buildbot/test/unit/schedulers/test_basic.py
+++ b/master/buildbot/test/unit/schedulers/test_basic.py
@@ -102,11 +102,13 @@ def getChangeClassificationsForTimer(self, sched_id, timer_name):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpScheduler()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.tearDownScheduler()
+        yield self.tear_down_test_reactor()
 
     # tests
 
@@ -352,11 +354,13 @@ def mkch(self, **kwargs):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpScheduler()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.tearDownScheduler()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_constructor_no_reason(self):
@@ -593,11 +597,13 @@ class AnyBranchScheduler(
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpScheduler()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.tearDownScheduler()
+        yield self.tear_down_test_reactor()
 
     def test_constructor_branch_forbidden(self):
         with self.assertRaises(config.ConfigErrors):
diff --git a/master/buildbot/test/unit/schedulers/test_canceller.py b/master/buildbot/test/unit/schedulers/test_canceller.py
index 2e14ab4b6db..05eb90259ed 100644
--- a/master/buildbot/test/unit/schedulers/test_canceller.py
+++ b/master/buildbot/test/unit/schedulers/test_canceller.py
@@ -49,7 +49,7 @@ def test_multiple_filters_on_builder(self, name, builder, props, expected):
 
 class TestOldBuildrequestTracker(unittest.TestCase, TestReactorMixin):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         filter = _OldBuildFilterSet()
 
         ss_filter = SourceStampFilter(
@@ -61,6 +61,10 @@ def setUp(self):
             self.reactor, filter, lambda ss: ss['branch'], self.on_cancel
         )
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def on_cancel(self, brid):
         self.cancellations.append(brid)
 
@@ -384,7 +388,7 @@ def test_check_builders_keys_not_list(self, name, value, error):
 class TestOldBuildCanceller(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantData=True, wantDb=True)
         self.master.mq.verifyMessages = False
 
@@ -393,8 +397,10 @@ def setUp(self):
 
         yield self.master.startService()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.master.stopService()
+        yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     def create_ss_dict(self, project, codebase, repository, branch):
         # Changes have the same structure for the attributes that we're using, so we reuse this
diff --git a/master/buildbot/test/unit/schedulers/test_canceller_buildset.py b/master/buildbot/test/unit/schedulers/test_canceller_buildset.py
index 9fceaa9ea27..fb54cbdbd9b 100644
--- a/master/buildbot/test/unit/schedulers/test_canceller_buildset.py
+++ b/master/buildbot/test/unit/schedulers/test_canceller_buildset.py
@@ -28,7 +28,7 @@
 class TestOldBuildCanceller(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantData=True, wantDb=True)
         self.master.mq.verifyMessages = False
 
@@ -37,8 +37,10 @@ def setUp(self):
 
         yield self.master.startService()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.master.stopService()
+        yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def insert_test_data(self):
diff --git a/master/buildbot/test/unit/schedulers/test_dependent.py b/master/buildbot/test/unit/schedulers/test_dependent.py
index afebea77f4a..ab0e8dc38b5 100644
--- a/master/buildbot/test/unit/schedulers/test_dependent.py
+++ b/master/buildbot/test/unit/schedulers/test_dependent.py
@@ -38,11 +38,13 @@
 class Dependent(scheduler.SchedulerMixin, TestReactorMixin, StateTestMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpScheduler()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.tearDownScheduler()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def makeScheduler(self, upstream=None):
diff --git a/master/buildbot/test/unit/schedulers/test_forcesched.py b/master/buildbot/test/unit/schedulers/test_forcesched.py
index 317da38a7e9..58178ea1212 100644
--- a/master/buildbot/test/unit/schedulers/test_forcesched.py
+++ b/master/buildbot/test/unit/schedulers/test_forcesched.py
@@ -48,11 +48,13 @@ class TestForceScheduler(
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpScheduler()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.tearDownScheduler()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def makeScheduler(self, name='testsched', builderNames=None, **kw):
diff --git a/master/buildbot/test/unit/schedulers/test_timed_Nightly.py b/master/buildbot/test/unit/schedulers/test_timed_Nightly.py
index 7aad90e65e9..6483d7e6f52 100644
--- a/master/buildbot/test/unit/schedulers/test_timed_Nightly.py
+++ b/master/buildbot/test/unit/schedulers/test_timed_Nightly.py
@@ -116,11 +116,13 @@ def mkch(self, **kwargs):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpScheduler()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.tearDownScheduler()
+        yield self.tear_down_test_reactor()
 
     def assertConsumingChanges(self, **kwargs):
         self.assertEqual(self.consumingChanges, kwargs)
diff --git a/master/buildbot/test/unit/schedulers/test_timed_NightlyBase.py b/master/buildbot/test/unit/schedulers/test_timed_NightlyBase.py
index 254172b3f96..3fd200a3026 100644
--- a/master/buildbot/test/unit/schedulers/test_timed_NightlyBase.py
+++ b/master/buildbot/test/unit/schedulers/test_timed_NightlyBase.py
@@ -31,9 +31,14 @@ class NightlyBase(scheduler.SchedulerMixin, TestReactorMixin, unittest.TestCase)
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpScheduler()
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        self.tearDownScheduler()
+        yield self.tear_down_test_reactor()
+
     def makeScheduler(self, firstBuildDuration=0, **kwargs):
         return self.attachScheduler(timed.NightlyBase(**kwargs), self.OBJECTID, self.SCHEDULERID)
 
diff --git a/master/buildbot/test/unit/schedulers/test_timed_NightlyTriggerable.py b/master/buildbot/test/unit/schedulers/test_timed_NightlyTriggerable.py
index cc19fdcff7d..0f780873c77 100644
--- a/master/buildbot/test/unit/schedulers/test_timed_NightlyTriggerable.py
+++ b/master/buildbot/test/unit/schedulers/test_timed_NightlyTriggerable.py
@@ -48,11 +48,13 @@ def makeScheduler(self, firstBuildDuration=0, **kwargs):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpScheduler()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.tearDownScheduler()
+        yield self.tear_down_test_reactor()
 
     # utilities
 
diff --git a/master/buildbot/test/unit/schedulers/test_timed_Periodic.py b/master/buildbot/test/unit/schedulers/test_timed_Periodic.py
index e6cd9c5bcdf..a7bba89b470 100644
--- a/master/buildbot/test/unit/schedulers/test_timed_Periodic.py
+++ b/master/buildbot/test/unit/schedulers/test_timed_Periodic.py
@@ -33,9 +33,14 @@ class Periodic(scheduler.SchedulerMixin, TestReactorMixin, unittest.TestCase):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpScheduler()
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        self.tearDownScheduler()
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def makeScheduler(self, firstBuildDuration=0, firstBuildError=False, exp_branch=None, **kwargs):
         self.sched = sched = timed.Periodic(**kwargs)
diff --git a/master/buildbot/test/unit/schedulers/test_timed_Timed.py b/master/buildbot/test/unit/schedulers/test_timed_Timed.py
index 517ec0b6a53..6545faf4fff 100644
--- a/master/buildbot/test/unit/schedulers/test_timed_Timed.py
+++ b/master/buildbot/test/unit/schedulers/test_timed_Timed.py
@@ -27,11 +27,13 @@ class Timed(scheduler.SchedulerMixin, TestReactorMixin, unittest.TestCase):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpScheduler()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.tearDownScheduler()
+        yield self.tear_down_test_reactor()
 
     class Subclass(timed.Timed):
         def getNextBuildTime(self, lastActuation):
diff --git a/master/buildbot/test/unit/schedulers/test_triggerable.py b/master/buildbot/test/unit/schedulers/test_triggerable.py
index 6ca1b0b83b8..df972260d29 100644
--- a/master/buildbot/test/unit/schedulers/test_triggerable.py
+++ b/master/buildbot/test/unit/schedulers/test_triggerable.py
@@ -38,15 +38,17 @@ class Triggerable(scheduler.SchedulerMixin, TestReactorMixin, unittest.TestCase)
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         # Necessary to get an assertable submitted_at time.
         self.reactor.advance(946684799)
 
         yield self.setUpScheduler()
         self.subscription = None
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.tearDownScheduler()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def makeScheduler(self, overrideBuildsetMethods=False, **kwargs):
diff --git a/master/buildbot/test/unit/schedulers/test_trysched.py b/master/buildbot/test/unit/schedulers/test_trysched.py
index b8ebec2501e..7facba036b6 100644
--- a/master/buildbot/test/unit/schedulers/test_trysched.py
+++ b/master/buildbot/test/unit/schedulers/test_trysched.py
@@ -35,11 +35,13 @@ class TryBase(scheduler.SchedulerMixin, TestReactorMixin, unittest.TestCase):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpScheduler()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.tearDownScheduler()
+        yield self.tear_down_test_reactor()
 
     def makeScheduler(self, **kwargs):
         return self.attachScheduler(
@@ -130,14 +132,16 @@ class Try_Jobdir(scheduler.SchedulerMixin, TestReactorMixin, unittest.TestCase):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpScheduler()
         self.jobdir = None
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.tearDownScheduler()
         if self.jobdir:
             shutil.rmtree(self.jobdir)
+        yield self.tear_down_test_reactor()
 
     # tests
 
@@ -874,11 +878,13 @@ class Try_Userpass_Perspective(scheduler.SchedulerMixin, TestReactorMixin, unitt
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpScheduler()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.tearDownScheduler()
+        yield self.tear_down_test_reactor()
 
     def makeScheduler(self, **kwargs):
         return self.attachScheduler(
@@ -1051,11 +1057,13 @@ class Try_Userpass(scheduler.SchedulerMixin, TestReactorMixin, unittest.TestCase
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpScheduler()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.tearDownScheduler()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def makeScheduler(self, **kwargs):
diff --git a/master/buildbot/test/unit/scripts/test_cleanupdb.py b/master/buildbot/test/unit/scripts/test_cleanupdb.py
index 12ac70333ac..613ed953f56 100644
--- a/master/buildbot/test/unit/scripts/test_cleanupdb.py
+++ b/master/buildbot/test/unit/scripts/test_cleanupdb.py
@@ -78,7 +78,7 @@ class TestCleanupDb(
     misc.StdoutAssertionsMixin, dirs.DirsMixin, TestReactorMixin, unittest.TestCase
 ):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setUpDirs('basedir')
         with open(os.path.join('basedir', 'buildbot.tac'), "w", encoding='utf-8') as f:
             f.write(
@@ -90,8 +90,10 @@ def setUp(self):
         self.setUpStdoutAssertions()
         self.ensureNoSqliteMemory()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.tearDownDirs()
+        yield self.tear_down_test_reactor()
 
     def ensureNoSqliteMemory(self):
         # test may use mysql or pg if configured in env
diff --git a/master/buildbot/test/unit/scripts/test_create_master.py b/master/buildbot/test/unit/scripts/test_create_master.py
index 1bfb30af62d..b3171d419e7 100644
--- a/master/buildbot/test/unit/scripts/test_create_master.py
+++ b/master/buildbot/test/unit/scripts/test_create_master.py
@@ -91,13 +91,15 @@ class TestCreateMasterFunctions(
     unittest.TestCase,
 ):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setUpDirs('test')
         self.basedir = os.path.abspath(os.path.join('test', 'basedir'))
         self.setUpStdoutAssertions()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.tearDownDirs()
+        yield self.tear_down_test_reactor()
 
     def assertInTacFile(self, str):
         with open(os.path.join('test', 'buildbot.tac'), encoding='utf-8') as f:
diff --git a/master/buildbot/test/unit/scripts/test_logwatcher.py b/master/buildbot/test/unit/scripts/test_logwatcher.py
index 8eafcbd375d..e9fdd2d8704 100644
--- a/master/buildbot/test/unit/scripts/test_logwatcher.py
+++ b/master/buildbot/test/unit/scripts/test_logwatcher.py
@@ -48,10 +48,14 @@ def setUp(self):
         self.setUpDirs('workdir')
         self.addCleanup(self.tearDownDirs)
 
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.spawned_process = mock.Mock()
         self.reactor.spawnProcess = mock.Mock(return_value=self.spawned_process)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_start(self):
         lw = MockedLogWatcher('workdir/test.log', _reactor=self.reactor)
         lw._start = mock.Mock()
diff --git a/master/buildbot/test/unit/scripts/test_upgrade_master.py b/master/buildbot/test/unit/scripts/test_upgrade_master.py
index 4a82eeea15b..0f273e02ced 100644
--- a/master/buildbot/test/unit/scripts/test_upgrade_master.py
+++ b/master/buildbot/test/unit/scripts/test_upgrade_master.py
@@ -114,13 +114,15 @@ class TestUpgradeMasterFunctions(
     unittest.TestCase,
 ):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setUpDirs('test')
         self.basedir = os.path.abspath(os.path.join('test', 'basedir'))
         self.setUpStdoutAssertions()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.tearDownDirs()
+        yield self.tear_down_test_reactor()
 
     def writeFile(self, path, contents):
         with open(path, "w", encoding='utf-8') as f:
diff --git a/master/buildbot/test/unit/steps/test_cmake.py b/master/buildbot/test/unit/steps/test_cmake.py
index 75fe023bf4e..d40f760352e 100644
--- a/master/buildbot/test/unit/steps/test_cmake.py
+++ b/master/buildbot/test/unit/steps/test_cmake.py
@@ -28,11 +28,13 @@
 class TestCMake(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def expect_and_run_command(self, *params):
         command = [CMake.DEFAULT_CMAKE, *list(params)]
diff --git a/master/buildbot/test/unit/steps/test_cppcheck.py b/master/buildbot/test/unit/steps/test_cppcheck.py
index e89f0aa0eb2..3a894063361 100644
--- a/master/buildbot/test/unit/steps/test_cppcheck.py
+++ b/master/buildbot/test/unit/steps/test_cppcheck.py
@@ -13,6 +13,7 @@
 #
 # Copyright Buildbot Team Members
 
+from twisted.internet import defer
 from twisted.trial import unittest
 
 from buildbot.process.properties import WithProperties
@@ -27,11 +28,13 @@
 
 class Cppcheck(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_success(self):
         self.setup_step(cppcheck.Cppcheck(enable=['all'], inconclusive=True))
diff --git a/master/buildbot/test/unit/steps/test_http.py b/master/buildbot/test/unit/steps/test_http.py
index cd813e21db4..fd139603089 100644
--- a/master/buildbot/test/unit/steps/test_http.py
+++ b/master/buildbot/test/unit/steps/test_http.py
@@ -66,7 +66,7 @@ def render_POST(self, request):
 
 class TestHTTPStep(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         if txrequests is None:
             raise unittest.SkipTest("Need to install txrequests to test http steps")
 
@@ -89,6 +89,7 @@ def tearDown(self):
             yield self.site.close_connections()
         finally:
             yield self.tear_down_test_build_step()
+            yield self.tear_down_test_reactor()
 
     def get_connection_string(self):
         return f"http://127.0.0.1:{self.port}"
diff --git a/master/buildbot/test/unit/steps/test_master.py b/master/buildbot/test/unit/steps/test_master.py
index 61d483c4a1c..3e79ee2566f 100644
--- a/master/buildbot/test/unit/steps/test_master.py
+++ b/master/buildbot/test/unit/steps/test_master.py
@@ -36,19 +36,21 @@
 
 class TestMasterShellCommand(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         if runtime.platformType == 'win32':
             self.comspec = os.environ.get(_COMSPEC_ENV)
             os.environ[_COMSPEC_ENV] = r'C:\WINDOWS\system32\cmd.exe'
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         if runtime.platformType == 'win32':
             if self.comspec:
                 os.environ[_COMSPEC_ENV] = self.comspec
             else:
                 del os.environ[_COMSPEC_ENV]
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_constr_args(self):
         self.setup_step(
@@ -168,11 +170,13 @@ def test_constr_args_descriptionSuffix(self):
 
 class TestSetProperty(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_simple(self):
         self.setup_step(
@@ -190,11 +194,13 @@ def test_simple(self):
 
 class TestLogRenderable(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_simple(self):
         self.setup_step(
@@ -211,11 +217,13 @@ def test_simple(self):
 
 class TestsSetProperties(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def doOneTest(self, **kwargs):
         # all three tests should create a 'a' property with 'b' value, all with different
@@ -242,11 +250,13 @@ def manipulate(props):
 
 class TestAssert(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_eq_pass(self):
         self.setup_step(master.Assert(Property("test_prop") == "foo"))
diff --git a/master/buildbot/test/unit/steps/test_maxq.py b/master/buildbot/test/unit/steps/test_maxq.py
index 208679462b0..a548c422141 100644
--- a/master/buildbot/test/unit/steps/test_maxq.py
+++ b/master/buildbot/test/unit/steps/test_maxq.py
@@ -13,6 +13,7 @@
 #
 # Copyright Buildbot Team Members
 
+from twisted.internet import defer
 from twisted.trial import unittest
 
 from buildbot import config
@@ -26,11 +27,13 @@
 
 class TestShellCommandExecution(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_testdir_required(self):
         with self.assertRaises(config.ConfigErrors):
diff --git a/master/buildbot/test/unit/steps/test_mswin.py b/master/buildbot/test/unit/steps/test_mswin.py
index ab3f192afc9..42314014f67 100644
--- a/master/buildbot/test/unit/steps/test_mswin.py
+++ b/master/buildbot/test/unit/steps/test_mswin.py
@@ -35,11 +35,13 @@ class TestRobocopySimple(TestBuildStepMixin, TestReactorMixin, unittest.TestCase
     """
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def _run_simple_test(
         self,
diff --git a/master/buildbot/test/unit/steps/test_package_deb_lintian.py b/master/buildbot/test/unit/steps/test_package_deb_lintian.py
index 46ed38376fa..52910777aab 100644
--- a/master/buildbot/test/unit/steps/test_package_deb_lintian.py
+++ b/master/buildbot/test/unit/steps/test_package_deb_lintian.py
@@ -13,6 +13,7 @@
 #
 # Copyright Buildbot Team Members
 
+from twisted.internet import defer
 from twisted.trial import unittest
 
 from buildbot import config
@@ -25,11 +26,13 @@
 
 class TestDebLintian(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_no_fileloc(self):
         with self.assertRaises(config.ConfigErrors):
diff --git a/master/buildbot/test/unit/steps/test_package_deb_pbuilder.py b/master/buildbot/test/unit/steps/test_package_deb_pbuilder.py
index 6173b6752c6..03f059dd71e 100644
--- a/master/buildbot/test/unit/steps/test_package_deb_pbuilder.py
+++ b/master/buildbot/test/unit/steps/test_package_deb_pbuilder.py
@@ -15,6 +15,7 @@
 
 import time
 
+from twisted.internet import defer
 from twisted.trial import unittest
 
 from buildbot import config
@@ -30,11 +31,13 @@
 
 class TestDebPbuilder(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_new(self):
         self.setup_step(pbuilder.DebPbuilder())
@@ -488,11 +491,13 @@ def test_othermirror(self):
 
 class TestDebCowbuilder(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_new(self):
         self.setup_step(pbuilder.DebCowbuilder())
@@ -639,11 +644,13 @@ def test_buildonly_reg(self):
 
 class TestUbuPbuilder(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_no_distribution(self):
         with self.assertRaises(config.ConfigErrors):
@@ -691,11 +698,13 @@ def test_new(self):
 
 class TestUbuCowbuilder(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_no_distribution(self):
         with self.assertRaises(config.ConfigErrors):
diff --git a/master/buildbot/test/unit/steps/test_package_rpm_mock.py b/master/buildbot/test/unit/steps/test_package_rpm_mock.py
index 6eb7f189c03..22a3022c273 100644
--- a/master/buildbot/test/unit/steps/test_package_rpm_mock.py
+++ b/master/buildbot/test/unit/steps/test_package_rpm_mock.py
@@ -13,6 +13,7 @@
 #
 # Copyright Buildbot Team Members
 
+from twisted.internet import defer
 from twisted.trial import unittest
 
 from buildbot import config
@@ -27,7 +28,7 @@
 
 class TestMock(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
     def tearDown(self):
@@ -108,11 +109,13 @@ def test_resultdir_renderable(self):
 
 class TestMockBuildSRPM(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_no_spec(self):
         with self.assertRaises(config.ConfigErrors):
@@ -149,11 +152,13 @@ def test_success(self):
 
 class TestMockRebuild(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_no_srpm(self):
         with self.assertRaises(config.ConfigErrors):
diff --git a/master/buildbot/test/unit/steps/test_package_rpm_rpmbuild.py b/master/buildbot/test/unit/steps/test_package_rpm_rpmbuild.py
index 3f5e904bc25..fbca59aa42f 100644
--- a/master/buildbot/test/unit/steps/test_package_rpm_rpmbuild.py
+++ b/master/buildbot/test/unit/steps/test_package_rpm_rpmbuild.py
@@ -30,11 +30,13 @@
 
 class RpmBuild(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_no_specfile(self):
         with self.assertRaises(config.ConfigErrors):
diff --git a/master/buildbot/test/unit/steps/test_package_rpm_rpmlint.py b/master/buildbot/test/unit/steps/test_package_rpm_rpmlint.py
index 19e93d4e41e..d633b126a30 100644
--- a/master/buildbot/test/unit/steps/test_package_rpm_rpmlint.py
+++ b/master/buildbot/test/unit/steps/test_package_rpm_rpmlint.py
@@ -13,6 +13,7 @@
 #
 # Copyright Buildbot Team Members
 
+from twisted.internet import defer
 from twisted.trial import unittest
 
 from buildbot.process.results import SUCCESS
@@ -24,11 +25,13 @@
 
 class TestRpmLint(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_success(self):
         self.setup_step(rpmlint.RpmLint())
diff --git a/master/buildbot/test/unit/steps/test_python.py b/master/buildbot/test/unit/steps/test_python.py
index 79cc9c76189..437af94a89c 100644
--- a/master/buildbot/test/unit/steps/test_python.py
+++ b/master/buildbot/test/unit/steps/test_python.py
@@ -125,11 +125,13 @@
 
 class BuildEPYDoc(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_sample(self):
         self.setup_step(python.BuildEPYDoc())
@@ -142,11 +144,13 @@ def test_sample(self):
 
 class PyLint(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     @parameterized.expand([('no_results', True), ('with_results', False)])
     def test_success(self, name, store_results):
@@ -439,11 +443,13 @@ def test_regex_parseable_1_3_1(self):
 
 class PyFlakes(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_success(self):
         self.setup_step(python.PyFlakes())
@@ -525,11 +531,13 @@ def test_misc(self):
 
 class TestSphinx(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_builddir_required(self):
         with self.assertRaises(config.ConfigErrors):
diff --git a/master/buildbot/test/unit/steps/test_python_twisted.py b/master/buildbot/test/unit/steps/test_python_twisted.py
index 6c00c4554d5..0c5366596d8 100644
--- a/master/buildbot/test/unit/steps/test_python_twisted.py
+++ b/master/buildbot/test/unit/steps/test_python_twisted.py
@@ -15,6 +15,7 @@
 
 import textwrap
 
+from twisted.internet import defer
 from twisted.trial import unittest
 
 from buildbot.process.properties import Property
@@ -93,11 +94,13 @@
 
 class Trial(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_run_env(self):
         self.setup_step(
@@ -397,11 +400,13 @@ def test_run_jobsProperties(self):
 
 class HLint(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_run_ok(self):
         self.setup_build(build_files=['foo.xhtml'])
@@ -466,11 +471,13 @@ def test_run_warnings(self):
 
 class RemovePYCs(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_run_ok(self):
         self.setup_step(python_twisted.RemovePYCs())
diff --git a/master/buildbot/test/unit/steps/test_renderable.py b/master/buildbot/test/unit/steps/test_renderable.py
index cd9090b951b..d24407cfb69 100644
--- a/master/buildbot/test/unit/steps/test_renderable.py
+++ b/master/buildbot/test/unit/steps/test_renderable.py
@@ -13,6 +13,7 @@
 #
 # Copyright Buildbot Team Members
 
+from twisted.internet import defer
 from twisted.trial import unittest
 
 from buildbot.process.buildstep import BuildStep
@@ -32,11 +33,13 @@ class TestBuildStepNameIsRenderable(
     TestBuildStepMixin, unittest.TestCase, TestReactorMixin, configmixin.ConfigErrorsMixin
 ):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_name_is_renderable(self):
         step = TestBuildStep(name=Interpolate('%(kw:foo)s', foo='bar'))
diff --git a/master/buildbot/test/unit/steps/test_shell.py b/master/buildbot/test/unit/steps/test_shell.py
index 8a4f449628c..f8cf6e7951d 100644
--- a/master/buildbot/test/unit/steps/test_shell.py
+++ b/master/buildbot/test/unit/steps/test_shell.py
@@ -40,11 +40,13 @@ class TestShellCommandExecution(
     TestBuildStepMixin, configmixin.ConfigErrorsMixin, TestReactorMixin, unittest.TestCase
 ):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_doStepIf_False(self):
         self.setup_step(shell.ShellCommand(command="echo hello", doStepIf=False))
@@ -180,11 +182,13 @@ def test_missing_command_error(self):
 
 class TreeSize(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_run_success(self):
         self.setup_step(shell.TreeSize())
@@ -216,11 +220,13 @@ def test_run_failed(self):
 
 class SetPropertyFromCommand(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_constructor_conflict(self):
         with self.assertRaises(config.ConfigErrors):
@@ -349,11 +355,13 @@ def test_error_none_set(self):
 
 class PerlModuleTest(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_new_version_success(self):
         self.setup_step(shell.PerlModuleTest(command="cmd"))
@@ -462,11 +470,13 @@ def test_old_version_failed(self):
 
 class Configure(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_class_attrs(self):
         step = shell.Configure()
@@ -484,11 +494,13 @@ class WarningCountingShellCommand(
     TestBuildStepMixin, configmixin.ConfigErrorsMixin, TestReactorMixin, unittest.TestCase
 ):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_no_warnings(self):
         self.setup_step(shell.WarningCountingShellCommand(workdir='w', command=['make']))
@@ -812,11 +824,13 @@ def test_missing_command_error(self):
 
 class Compile(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_class_args(self):
         # since this step is just a pre-configured WarningCountingShellCommand,
@@ -832,11 +846,13 @@ def test_class_args(self):
 
 class Test(TestBuildStepMixin, configmixin.ConfigErrorsMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_setTestResults(self):
         step = self.setup_step(shell.Test())
diff --git a/master/buildbot/test/unit/steps/test_shellsequence.py b/master/buildbot/test/unit/steps/test_shellsequence.py
index 66eff46e848..e8b84b599f1 100644
--- a/master/buildbot/test/unit/steps/test_shellsequence.py
+++ b/master/buildbot/test/unit/steps/test_shellsequence.py
@@ -38,7 +38,7 @@ class TestOneShellCommand(
     TestBuildStepMixin, configmixin.ConfigErrorsMixin, TestReactorMixin, unittest.TestCase
 ):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
     def tearDown(self):
diff --git a/master/buildbot/test/unit/steps/test_source_base_Source.py b/master/buildbot/test/unit/steps/test_source_base_Source.py
index 056900a48b6..6efd4e437b4 100644
--- a/master/buildbot/test/unit/steps/test_source_base_Source.py
+++ b/master/buildbot/test/unit/steps/test_source_base_Source.py
@@ -32,11 +32,13 @@ def startVC(self):
 
 class TestSource(sourcesteps.SourceStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def setup_deferred_mock(self):
         m = mock.Mock()
@@ -168,11 +170,13 @@ def test_old_style_source_step_throws_exception(self):
 
 class TestSourceDescription(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_constructor_args_strings(self):
         step = Source(
@@ -204,11 +208,13 @@ def mode_incremental(self):
 
 class TestSourceAttrGroup(sourcesteps.SourceStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_attrgroup_hasattr(self):
         step = AttrGroup()
diff --git a/master/buildbot/test/unit/steps/test_source_bzr.py b/master/buildbot/test/unit/steps/test_source_bzr.py
index 7d8c8a40b47..ac5bbb9a079 100644
--- a/master/buildbot/test/unit/steps/test_source_bzr.py
+++ b/master/buildbot/test/unit/steps/test_source_bzr.py
@@ -16,6 +16,7 @@
 
 import os
 
+from twisted.internet import defer
 from twisted.internet import error
 from twisted.python.reflect import namedModule
 from twisted.trial import unittest
@@ -37,11 +38,13 @@
 
 class TestBzr(sourcesteps.SourceStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setUpSourceStep()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownSourceStep()
+        yield self.tearDownSourceStep()
+        yield self.tear_down_test_reactor()
 
     def test_mode_full(self):
         self.setup_step(
diff --git a/master/buildbot/test/unit/steps/test_source_cvs.py b/master/buildbot/test/unit/steps/test_source_cvs.py
index fd428b0579f..199563f3ce6 100644
--- a/master/buildbot/test/unit/steps/test_source_cvs.py
+++ b/master/buildbot/test/unit/steps/test_source_cvs.py
@@ -15,6 +15,7 @@
 
 import time
 
+from twisted.internet import defer
 from twisted.internet import error
 from twisted.trial import unittest
 
@@ -37,11 +38,13 @@
 
 class TestCVS(sourcesteps.SourceStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setUpSourceStep()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownSourceStep()
+        yield self.tearDownSourceStep()
+        yield self.tear_down_test_reactor()
 
     def setup_step(self, step, *args, **kwargs):
         super().setup_step(step, *args, **kwargs)
diff --git a/master/buildbot/test/unit/steps/test_source_darcs.py b/master/buildbot/test/unit/steps/test_source_darcs.py
index 43116dfe224..393bd8c5ae1 100644
--- a/master/buildbot/test/unit/steps/test_source_darcs.py
+++ b/master/buildbot/test/unit/steps/test_source_darcs.py
@@ -13,6 +13,7 @@
 #
 # Copyright Buildbot Team Members
 
+from twisted.internet import defer
 from twisted.internet import error
 from twisted.trial import unittest
 
@@ -33,11 +34,13 @@
 
 class TestDarcs(sourcesteps.SourceStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setUpSourceStep()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownSourceStep()
+        yield self.tearDownSourceStep()
+        yield self.tear_down_test_reactor()
 
     def test_no_empty_step_config(self):
         with self.assertRaises(config.ConfigErrors):
diff --git a/master/buildbot/test/unit/steps/test_source_gerrit.py b/master/buildbot/test/unit/steps/test_source_gerrit.py
index 0ef8505b31b..211f9f50f79 100644
--- a/master/buildbot/test/unit/steps/test_source_gerrit.py
+++ b/master/buildbot/test/unit/steps/test_source_gerrit.py
@@ -13,6 +13,7 @@
 #
 # Copyright Buildbot Team Members
 
+from twisted.internet import defer
 from twisted.trial import unittest
 
 from buildbot.process.results import SUCCESS
@@ -29,11 +30,13 @@ class TestGerrit(
     sourcesteps.SourceStepMixin, config.ConfigErrorsMixin, TestReactorMixin, unittest.TestCase
 ):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setUpSourceStep()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownSourceStep()
+        yield self.tearDownSourceStep()
+        yield self.tear_down_test_reactor()
 
     def test_mode_full_clean(self):
         self.setup_step(
diff --git a/master/buildbot/test/unit/steps/test_source_git.py b/master/buildbot/test/unit/steps/test_source_git.py
index 17a1b3113d3..5e7ebe91d3a 100644
--- a/master/buildbot/test/unit/steps/test_source_git.py
+++ b/master/buildbot/test/unit/steps/test_source_git.py
@@ -48,12 +48,14 @@ class TestGit(
     stepClass = git.Git
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.sourceName = self.stepClass.__name__
         return self.setUpSourceStep()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownSourceStep()
+        yield self.tearDownSourceStep()
+        yield self.tear_down_test_reactor()
 
     def test_mode_full_filters_2_26(self):
         self.setup_step(
@@ -4185,7 +4187,7 @@ class TestGitPush(
     stepClass = git.GitPush
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
     def tearDown(self):
@@ -4668,7 +4670,7 @@ class TestGitTag(TestBuildStepMixin, config.ConfigErrorsMixin, TestReactorMixin,
     stepClass = git.GitTag
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
     def tearDown(self):
@@ -4764,14 +4766,16 @@ class TestGitCommit(
     stepClass = git.GitCommit
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.message_list = ['my commit', '42']
         self.path_list = ['file1.txt', 'file2.txt']
 
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_add_fail(self):
         self.setup_step(
diff --git a/master/buildbot/test/unit/steps/test_source_gitlab.py b/master/buildbot/test/unit/steps/test_source_gitlab.py
index bf83370fd36..3c6e1f0b021 100644
--- a/master/buildbot/test/unit/steps/test_source_gitlab.py
+++ b/master/buildbot/test/unit/steps/test_source_gitlab.py
@@ -13,6 +13,7 @@
 #
 # Copyright Buildbot Team Members
 
+from twisted.internet import defer
 from twisted.trial import unittest
 
 from buildbot.process.results import SUCCESS
@@ -31,7 +32,7 @@ class TestGitLab(
     stepClass = gitlab.GitLab
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.sourceName = self.stepClass.__name__
         return self.setUpSourceStep()
 
@@ -53,8 +54,10 @@ def setup_step(self, step, args, **kwargs):
         step.build.properties.setProperty("target_project_id", 239, "gitlab target project ID")
         return step
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownSourceStep()
+        yield self.tearDownSourceStep()
+        yield self.tear_down_test_reactor()
 
     def test_with_merge_branch(self):
         self.setup_step(
diff --git a/master/buildbot/test/unit/steps/test_source_mercurial.py b/master/buildbot/test/unit/steps/test_source_mercurial.py
index 66ff7a8d072..478e920d73a 100644
--- a/master/buildbot/test/unit/steps/test_source_mercurial.py
+++ b/master/buildbot/test/unit/steps/test_source_mercurial.py
@@ -13,6 +13,7 @@
 #
 # Copyright Buildbot Team Members
 
+from twisted.internet import defer
 from twisted.internet import error
 from twisted.python.reflect import namedModule
 from twisted.trial import unittest
@@ -34,11 +35,13 @@
 
 class TestMercurial(sourcesteps.SourceStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setUpSourceStep()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownSourceStep()
+        yield self.tearDownSourceStep()
+        yield self.tear_down_test_reactor()
 
     def patch_workerVersionIsOlderThan(self, result):
         self.patch(mercurial.Mercurial, 'workerVersionIsOlderThan', lambda x, y, z: result)
diff --git a/master/buildbot/test/unit/steps/test_source_mtn.py b/master/buildbot/test/unit/steps/test_source_mtn.py
index 4e5b3793083..b6378097936 100644
--- a/master/buildbot/test/unit/steps/test_source_mtn.py
+++ b/master/buildbot/test/unit/steps/test_source_mtn.py
@@ -14,6 +14,7 @@
 # Copyright Buildbot Team Members
 
 
+from twisted.internet import defer
 from twisted.internet import error
 from twisted.trial import unittest
 
@@ -41,11 +42,13 @@ class TestMonotone(
     MTN_VER = 'monotone 1.0 (base revision: UNKNOWN_REV)'
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setUpSourceStep()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownSourceStep()
+        yield self.tearDownSourceStep()
+        yield self.tear_down_test_reactor()
 
     def test_mode_full_clean(self):
         self.setup_step(
diff --git a/master/buildbot/test/unit/steps/test_source_p4.py b/master/buildbot/test/unit/steps/test_source_p4.py
index b75c59dd0cb..e33b41a2843 100644
--- a/master/buildbot/test/unit/steps/test_source_p4.py
+++ b/master/buildbot/test/unit/steps/test_source_p4.py
@@ -17,6 +17,7 @@
 import platform
 import textwrap
 
+from twisted.internet import defer
 from twisted.internet import error
 from twisted.python import reflect
 from twisted.trial import unittest
@@ -36,11 +37,13 @@
 
 class TestP4(sourcesteps.SourceStepMixin, TestReactorMixin, ConfigErrorsMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setUpSourceStep()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownSourceStep()
+        yield self.tearDownSourceStep()
+        yield self.tear_down_test_reactor()
 
     def setup_step(self, step, args=None, patch=None, **kwargs):
         if args is None:
diff --git a/master/buildbot/test/unit/steps/test_source_repo.py b/master/buildbot/test/unit/steps/test_source_repo.py
index 15c6685f8f8..10f5d2f9b00 100644
--- a/master/buildbot/test/unit/steps/test_source_repo.py
+++ b/master/buildbot/test/unit/steps/test_source_repo.py
@@ -13,6 +13,7 @@
 #
 # Copyright Buildbot Team Members
 
+from twisted.internet import defer
 from twisted.trial import unittest
 
 from buildbot.changes.changes import Change
@@ -60,13 +61,15 @@ def test_parse3(self):
 
 class TestRepo(sourcesteps.SourceStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.shouldRetry = False
         self.logEnviron = True
         return self.setUpSourceStep()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownSourceStep()
+        yield self.tearDownSourceStep()
+        yield self.tear_down_test_reactor()
 
     def shouldLogEnviron(self):
         r = self.logEnviron
diff --git a/master/buildbot/test/unit/steps/test_source_svn.py b/master/buildbot/test/unit/steps/test_source_svn.py
index 7acb85c21ff..921c8902c59 100644
--- a/master/buildbot/test/unit/steps/test_source_svn.py
+++ b/master/buildbot/test/unit/steps/test_source_svn.py
@@ -121,11 +121,13 @@ class TestSVN(sourcesteps.SourceStepMixin, TestReactorMixin, unittest.TestCase):
                             </info>"""
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setUpSourceStep()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownSourceStep()
+        yield self.tearDownSourceStep()
+        yield self.tear_down_test_reactor()
 
     def patch_workerVersionIsOlderThan(self, result):
         self.patch(svn.SVN, 'workerVersionIsOlderThan', lambda x, y, z: result)
diff --git a/master/buildbot/test/unit/steps/test_subunit.py b/master/buildbot/test/unit/steps/test_subunit.py
index 0af83a07233..6ae22bbc245 100644
--- a/master/buildbot/test/unit/steps/test_subunit.py
+++ b/master/buildbot/test/unit/steps/test_subunit.py
@@ -17,6 +17,7 @@
 import re
 import sys
 
+from twisted.internet import defer
 from twisted.trial import unittest
 
 from buildbot.process.results import FAILURE
@@ -55,11 +56,13 @@ def setUp(self):
         if TestProtocolClient is None:
             raise unittest.SkipTest("Need to install python-subunit to test subunit step")
 
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_empty(self):
         self.setup_step(subunit.SubunitShellCommand(command='test'))
diff --git a/master/buildbot/test/unit/steps/test_transfer.py b/master/buildbot/test/unit/steps/test_transfer.py
index 5faf8c3950a..4f92d22fd22 100644
--- a/master/buildbot/test/unit/steps/test_transfer.py
+++ b/master/buildbot/test/unit/steps/test_transfer.py
@@ -43,16 +43,18 @@
 
 class TestFileUpload(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         fd, self.destfile = tempfile.mkstemp()
         os.close(fd)
         os.unlink(self.destfile)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         if os.path.exists(self.destfile):
             os.unlink(self.destfile)
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def testConstructorModeType(self):
         with self.assertRaises(config.ConfigErrors):
@@ -309,18 +311,20 @@ def test_init_positional_args(self):
 
 class TestDirectoryUpload(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.destdir = os.path.abspath('destdir')
         if os.path.exists(self.destdir):
             shutil.rmtree(self.destdir)
 
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         if os.path.exists(self.destdir):
             shutil.rmtree(self.destdir)
 
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def testBasic(self):
         self.setup_step(transfer.DirectoryUpload(workersrc="srcdir", masterdest=self.destdir))
@@ -493,18 +497,20 @@ def test_init_positional_args(self):
 
 class TestMultipleFileUpload(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.destdir = os.path.abspath('destdir')
         if os.path.exists(self.destdir):
             shutil.rmtree(self.destdir)
 
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         if os.path.exists(self.destdir):
             shutil.rmtree(self.destdir)
 
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def testEmpty(self):
         self.setup_step(transfer.MultipleFileUpload(workersrcs=[], masterdest=self.destdir))
@@ -936,16 +942,19 @@ def test_init_positional_args(self):
 
 class TestFileDownload(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         fd, self.destfile = tempfile.mkstemp()
         os.close(fd)
         os.unlink(self.destfile)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         if os.path.exists(self.destfile):
             os.unlink(self.destfile)
-        return self.tear_down_test_build_step()
+
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_init_workerdest_keyword(self):
         step = transfer.FileDownload(mastersrc='srcfile', workerdest='dstfile')
@@ -1046,11 +1055,13 @@ def test_no_file(self):
 
 class TestStringDownload(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     # check that ConfigErrors is raised on invalid 'mode' argument
 
@@ -1154,11 +1165,13 @@ def test_init_positional_args(self):
 
 class TestJSONStringDownload(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def testBasic(self):
@@ -1255,11 +1268,13 @@ def test_init_positional_args(self):
 
 class TestJSONPropertiesDownload(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def testBasic(self):
diff --git a/master/buildbot/test/unit/steps/test_trigger.py b/master/buildbot/test/unit/steps/test_trigger.py
index 3a72992b08a..84d1757f8dd 100644
--- a/master/buildbot/test/unit/steps/test_trigger.py
+++ b/master/buildbot/test/unit/steps/test_trigger.py
@@ -100,11 +100,13 @@ def BRID_TO_BUILD_NUMBER(brid):
 
 class TestTrigger(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def setup_step(self, step, sourcestampsInBuild=None, gotRevisionsInBuild=None, *args, **kwargs):
diff --git a/master/buildbot/test/unit/steps/test_vstudio.py b/master/buildbot/test/unit/steps/test_vstudio.py
index 93c846c7a3f..1fb64daa743 100644
--- a/master/buildbot/test/unit/steps/test_vstudio.py
+++ b/master/buildbot/test/unit/steps/test_vstudio.py
@@ -228,11 +228,13 @@ class VisualStudio(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     """
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_default_config(self):
         vs = vstudio.VisualStudio()
@@ -349,11 +351,13 @@ def test_rendering(self):
 
 class TestVC6(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def getExpectedEnv(self, installdir, LIB=None, p=None, i=None):
         include = [
@@ -447,11 +451,13 @@ def test_env_prepend(self):
 
 class TestVC7(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def getExpectedEnv(self, installdir, LIB=None, p=None, i=None):
         include = [
@@ -582,11 +588,13 @@ def getExpectedEnv(self, installdir, x64=False, LIB=None, i=None, p=None):
 
 class TestVC8(VC8ExpectedEnvMixin, TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_args(self):
         self.setup_step(vstudio.VC8(projectfile='pf', config='cfg', project='pj', arch='arch'))
@@ -643,11 +651,13 @@ def test_rendering(self):
 
 class TestVCExpress9(VC8ExpectedEnvMixin, TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_args(self):
         self.setup_step(vstudio.VCExpress9(projectfile='pf', config='cfg', project='pj'))
@@ -700,11 +710,13 @@ def test_mode_build_env(self):
 
 class TestVC9(VC8ExpectedEnvMixin, TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_installdir(self):
         self.setup_step(vstudio.VC9(projectfile='pf', config='cfg', project='pj'))
@@ -721,11 +733,13 @@ def test_installdir(self):
 
 class TestVC10(VC8ExpectedEnvMixin, TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_installdir(self):
         self.setup_step(vstudio.VC10(projectfile='pf', config='cfg', project='pj'))
@@ -742,11 +756,13 @@ def test_installdir(self):
 
 class TestVC11(VC8ExpectedEnvMixin, TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_installdir(self):
         self.setup_step(vstudio.VC11(projectfile='pf', config='cfg', project='pj'))
@@ -763,11 +779,13 @@ def test_installdir(self):
 
 class TestMsBuild(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_no_platform(self):
@@ -865,11 +883,13 @@ def test_rebuild_solution(self):
 
 class TestMsBuild141(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_no_platform(self):
@@ -985,11 +1005,13 @@ def test_aliases_MsBuild15(self):
 
 class TestMsBuild16(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_version_range_is_correct(self):
         self.setup_step(
@@ -1012,11 +1034,13 @@ def test_version_range_is_correct(self):
 
 class TestMsBuild17(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_version_range_is_correct(self):
         self.setup_step(
diff --git a/master/buildbot/test/unit/steps/test_worker.py b/master/buildbot/test/unit/steps/test_worker.py
index 9a8da907ad9..cefa8e0693a 100644
--- a/master/buildbot/test/unit/steps/test_worker.py
+++ b/master/buildbot/test/unit/steps/test_worker.py
@@ -42,11 +42,13 @@
 
 class TestSetPropertiesFromEnv(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_simple(self):
         self.setup_step(
@@ -81,11 +83,13 @@ def test_case_folding(self):
 
 class TestFileExists(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_found(self):
         self.setup_step(worker.FileExists(file="x"))
@@ -123,11 +127,13 @@ def test_old_version(self):
 
 class TestCopyDirectory(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_success(self):
         self.setup_step(worker.CopyDirectory(src="s", dest="d"))
@@ -166,11 +172,13 @@ def test_render(self):
 
 class TestRemoveDirectory(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_success(self):
         self.setup_step(worker.RemoveDirectory(dir="d"))
@@ -194,11 +202,13 @@ def test_render(self):
 
 class TestMakeDirectory(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_success(self):
         self.setup_step(worker.MakeDirectory(dir="d"))
@@ -235,11 +245,13 @@ def run(self):
 
 class TestCompositeStepMixin(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_runRemoteCommand(self):
         cmd_args = ('foo', {'bar': False})
diff --git a/master/buildbot/test/unit/test_download_secret_to_worker.py b/master/buildbot/test/unit/test_download_secret_to_worker.py
index fcd2bb11182..6d53bd9ec01 100644
--- a/master/buildbot/test/unit/test_download_secret_to_worker.py
+++ b/master/buildbot/test/unit/test_download_secret_to_worker.py
@@ -17,6 +17,7 @@
 import os
 import stat
 
+from twisted.internet import defer
 from twisted.python.filepath import FilePath
 from twisted.trial import unittest
 
@@ -37,14 +38,16 @@ class TestDownloadFileSecretToWorkerCommand(
     TestBuildStepMixin, TestReactorMixin, unittest.TestCase
 ):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         tempdir = FilePath(self.mktemp())
         tempdir.createDirectory()
         self.temp_path = tempdir.path
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def testBasic(self):
         self.setup_step(
@@ -79,14 +82,16 @@ def testBasic(self):
 
 class TestRemoveWorkerFileSecretCommand30(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         tempdir = FilePath(self.mktemp())
         tempdir.createDirectory()
         self.temp_path = tempdir.path
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def testBasic(self):
         self.setup_build(worker_version={'*': '3.0'})
@@ -119,14 +124,16 @@ class TestRemoveFileSecretToWorkerCommand(
     TestBuildStepMixin, configmixin.ConfigErrorsMixin, TestReactorMixin, unittest.TestCase
 ):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         tempdir = FilePath(self.mktemp())
         tempdir.createDirectory()
         self.temp_path = tempdir.path
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def testBasic(self):
         self.setup_step(
diff --git a/master/buildbot/test/unit/test_fake_httpclientservice.py b/master/buildbot/test/unit/test_fake_httpclientservice.py
index 19586fa8994..cd3dec8dc5f 100644
--- a/master/buildbot/test/unit/test_fake_httpclientservice.py
+++ b/master/buildbot/test/unit/test_fake_httpclientservice.py
@@ -43,7 +43,7 @@ def doGetRoot(self):
 class Test(unittest.TestCase, TestReactorMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        yield self.setup_test_reactor()
+        yield self.setup_test_reactor(auto_tear_down=False)
 
         baseurl = 'http://127.0.0.1:8080'
         master = yield fakemaster.make_master(self)
@@ -54,6 +54,10 @@ def setUp(self):
         yield self.tested.setServiceParent(master)
         yield master.startService()
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_root(self):
         self._http.expect("get", "/", content_json={'foo': 'bar'})
diff --git a/master/buildbot/test/unit/test_fake_secrets_manager.py b/master/buildbot/test/unit/test_fake_secrets_manager.py
index 2bd98574615..1f28dc0af8e 100644
--- a/master/buildbot/test/unit/test_fake_secrets_manager.py
+++ b/master/buildbot/test/unit/test_fake_secrets_manager.py
@@ -11,12 +11,16 @@
 class TestSecretsManager(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         self.master.config.secretsProviders = [
             FakeSecretStorage(secretdict={"foo": "bar", "other": "value"})
         ]
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def testGetManagerService(self):
         secret_service_manager = SecretManager()
diff --git a/master/buildbot/test/unit/test_interpolate_secrets.py b/master/buildbot/test/unit/test_interpolate_secrets.py
index 449a4c0ef5e..ae882384edb 100644
--- a/master/buildbot/test/unit/test_interpolate_secrets.py
+++ b/master/buildbot/test/unit/test_interpolate_secrets.py
@@ -21,7 +21,7 @@ def __init__(self, master):
 class TestInterpolateSecrets(TestReactorMixin, unittest.TestCase, ConfigErrorsMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         fakeStorageService = FakeSecretStorage()
         fakeStorageService.reconfigService(secretdict={"foo": "bar", "other": "value"})
@@ -30,6 +30,10 @@ def setUp(self):
         yield self.secretsrv.setServiceParent(self.master)
         self.build = FakeBuildWithMaster(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_secret(self):
         command = Interpolate("echo %(secret:foo)s")
@@ -48,10 +52,14 @@ def test_secret_not_found(self):
 class TestInterpolateSecretsNoService(TestReactorMixin, unittest.TestCase, ConfigErrorsMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         self.build = FakeBuildWithMaster(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_secret(self):
         command = Interpolate("echo %(secret:fuo)s")
@@ -64,7 +72,7 @@ def test_secret(self):
 class TestInterpolateSecretsHiddenSecrets(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         fakeStorageService = FakeSecretStorage()
         password = "bar"
@@ -76,6 +84,10 @@ def setUp(self):
         yield self.secretsrv.setServiceParent(self.master)
         self.build = FakeBuildWithMaster(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_secret(self):
         command = Interpolate("echo %(secret:foo)s")
diff --git a/master/buildbot/test/unit/test_janitor_configurator.py b/master/buildbot/test/unit/test_janitor_configurator.py
index 6679774c361..8df1cf8f216 100644
--- a/master/buildbot/test/unit/test_janitor_configurator.py
+++ b/master/buildbot/test/unit/test_janitor_configurator.py
@@ -68,12 +68,14 @@ class LogChunksJanitorTests(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setup_test_build_step()
         self.patch(janitor, "now", lambda: datetime.datetime(year=2017, month=1, day=1))
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_basic(self):
diff --git a/master/buildbot/test/unit/test_machine_generic.py b/master/buildbot/test/unit/test_machine_generic.py
index 39e9b6ea51f..7ac46d457d3 100644
--- a/master/buildbot/test/unit/test_machine_generic.py
+++ b/master/buildbot/test/unit/test_machine_generic.py
@@ -55,11 +55,12 @@ class TestActions(
     MasterRunProcessMixin, config.ConfigErrorsMixin, TestReactorMixin, unittest.TestCase
 ):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_master_run_process()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        pass
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_local_wake_action(self):
@@ -262,12 +263,16 @@ def test_remote_ssh_suspend_action_no_keys(self, write_local_file_mock, temp_dir
 class TestHttpAction(config.ConfigErrorsMixin, TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         self.http = yield fakehttpclientservice.HTTPClientService.getService(
             self.master, self, "http://localhost/request"
         )
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_http_wrong_method(self):
         manager = FakeManager(self.master)
diff --git a/master/buildbot/test/unit/test_master.py b/master/buildbot/test/unit/test_master.py
index febdc5da3e0..ae369945861 100644
--- a/master/buildbot/test/unit/test_master.py
+++ b/master/buildbot/test/unit/test_master.py
@@ -80,7 +80,7 @@ def test_configfile_default(self):
 class StartupAndReconfig(dirs.DirsMixin, logging.LoggingMixin, TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setUpLogging()
         self.basedir = os.path.abspath('basedir')
         yield self.setUpDirs(self.basedir)
@@ -107,8 +107,10 @@ def setUp(self):
         self.data = self.master.data = fakedata.FakeDataConnector(self.master, self)
         yield self.data.setServiceParent(self.master)
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tearDownDirs()
+        yield self.tearDownDirs()
+        yield self.tear_down_test_reactor()
 
     # tests
     @defer.inlineCallbacks
diff --git a/master/buildbot/test/unit/test_mq.py b/master/buildbot/test/unit/test_mq.py
index 19ff407ada9..34190bf10c5 100644
--- a/master/buildbot/test/unit/test_mq.py
+++ b/master/buildbot/test/unit/test_mq.py
@@ -133,16 +133,24 @@ def test_waitUntilEvent_check_false(self):
 class TestFakeMQ(TestReactorMixin, unittest.TestCase, Tests):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True)
         self.mq = self.master.mq
         self.mq.verifyMessages = False
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
 
 class TestSimpleMQ(TestReactorMixin, unittest.TestCase, RealTests):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         self.mq = simple.SimpleMQ()
         yield self.mq.setServiceParent(self.master)
+
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
diff --git a/master/buildbot/test/unit/test_mq_connector.py b/master/buildbot/test/unit/test_mq_connector.py
index dd14d3135c1..69351e5bbcd 100644
--- a/master/buildbot/test/unit/test_mq_connector.py
+++ b/master/buildbot/test/unit/test_mq_connector.py
@@ -42,12 +42,16 @@ def startConsuming(self, callback, filter, persistent_name=None):
 class MQConnector(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         self.mqconfig = self.master.config.mq = {}
         self.conn = connector.MQConnector()
         yield self.conn.setServiceParent(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def patchFakeMQ(self, name='fake'):
         self.patch(
             connector.MQConnector,
diff --git a/master/buildbot/test/unit/test_mq_simple.py b/master/buildbot/test/unit/test_mq_simple.py
index 29439d8c6d8..910cdccce21 100644
--- a/master/buildbot/test/unit/test_mq_simple.py
+++ b/master/buildbot/test/unit/test_mq_simple.py
@@ -26,7 +26,7 @@
 class SimpleMQ(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         self.mq = simple.SimpleMQ()
         self.mq.setServiceParent(self.master)
@@ -36,6 +36,7 @@ def setUp(self):
     def tearDown(self):
         if self.mq.running:
             yield self.mq.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_forward_data(self):
diff --git a/master/buildbot/test/unit/test_mq_wamp.py b/master/buildbot/test/unit/test_mq_wamp.py
index d984ba35275..51bf1d72b4d 100644
--- a/master/buildbot/test/unit/test_mq_wamp.py
+++ b/master/buildbot/test/unit/test_mq_wamp.py
@@ -126,7 +126,7 @@ class WampMQ(TestReactorMixin, unittest.TestCase):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         self.master.wamp = FakeWampConnector()
         self.mq = wamp.WampMQ()
@@ -137,6 +137,7 @@ def setUp(self):
     def tearDown(self):
         if self.mq.running:
             yield self.mq.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_startConsuming_basic(self):
@@ -248,7 +249,7 @@ class WampMQReal(TestReactorMixin, unittest.TestCase):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         if "WAMP_ROUTER_URL" not in os.environ:
             raise unittest.SkipTest(self.HOW_TO_RUN)
         self.master = yield fakemaster.make_master(self)
@@ -261,8 +262,10 @@ def setUp(self):
         config.mq['router_url'] = os.environ["WAMP_ROUTER_URL"]
         yield self.connector.reconfigServiceWithBuildbotConfig(config)
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.master.stopService()
+        yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_forward_data(self):
diff --git a/master/buildbot/test/unit/test_secret_in_passwordstore.py b/master/buildbot/test/unit/test_secret_in_passwordstore.py
index ecf132eae03..3f86e804b39 100644
--- a/master/buildbot/test/unit/test_secret_in_passwordstore.py
+++ b/master/buildbot/test/unit/test_secret_in_passwordstore.py
@@ -33,7 +33,7 @@ class TestSecretInPass(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_master_run_process()
         self.master = yield fakemaster.make_master(self)
         with mock.patch.object(Path, "is_file", return_value=True):
@@ -45,6 +45,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.srvpass.stopService()
+        yield self.tear_down_test_reactor()
 
     def create_temp_dir(self, dirname):
         tempdir = FilePath(self.mktemp())
diff --git a/master/buildbot/test/unit/test_secret_rendered_service.py b/master/buildbot/test/unit/test_secret_rendered_service.py
index 237906885e1..894294677d4 100644
--- a/master/buildbot/test/unit/test_secret_rendered_service.py
+++ b/master/buildbot/test/unit/test_secret_rendered_service.py
@@ -25,7 +25,7 @@ def returnRenderedSecrets(self, secretKey):
 class TestRenderSecrets(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         fakeStorageService = FakeSecretStorage(secretdict={"foo": "bar", "other": "value"})
         self.secretsrv = SecretManager()
@@ -38,6 +38,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_secret_rendered(self):
diff --git a/master/buildbot/test/unit/test_stats_service.py b/master/buildbot/test/unit/test_stats_service.py
index 89afbeaeb28..bf957da383b 100644
--- a/master/buildbot/test/unit/test_stats_service.py
+++ b/master/buildbot/test/unit/test_stats_service.py
@@ -45,7 +45,7 @@ class TestStatsServicesBase(TestReactorMixin, unittest.TestCase):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantData=True, wantDb=True)
 
         yield self.master.db.insert_test_data([
@@ -62,6 +62,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
 
 class TestStatsServicesConfiguration(TestStatsServicesBase):
diff --git a/master/buildbot/test/unit/test_steps_git_diffinfo.py b/master/buildbot/test/unit/test_steps_git_diffinfo.py
index d8c18d2e2d0..15940f90ef8 100644
--- a/master/buildbot/test/unit/test_steps_git_diffinfo.py
+++ b/master/buildbot/test/unit/test_steps_git_diffinfo.py
@@ -13,6 +13,7 @@
 #
 # Copyright Buildbot Team Members
 
+from twisted.internet import defer
 from twisted.trial import unittest
 
 from buildbot.process import results
@@ -32,11 +33,13 @@ class TestDiffInfo(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
         skip = 'unidiff is required for GitDiffInfo tests'
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     def test_merge_base_failure(self):
         self.setup_step(gitdiffinfo.GitDiffInfo())
diff --git a/master/buildbot/test/unit/test_steps_mixin.py b/master/buildbot/test/unit/test_steps_mixin.py
index b150ad64e2b..97976a64c5d 100644
--- a/master/buildbot/test/unit/test_steps_mixin.py
+++ b/master/buildbot/test/unit/test_steps_mixin.py
@@ -48,11 +48,13 @@ def run(self):
 
 class TestTestBuildStepMixin(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         return self.setup_test_build_step()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.tear_down_test_build_step()
+        yield self.tear_down_test_build_step()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_setup_build(self):
diff --git a/master/buildbot/test/unit/test_wamp_connector.py b/master/buildbot/test/unit/test_wamp_connector.py
index cd0b44660dc..9e6505e5401 100644
--- a/master/buildbot/test/unit/test_wamp_connector.py
+++ b/master/buildbot/test/unit/test_wamp_connector.py
@@ -59,7 +59,7 @@ class TestedWampConnector(connector.WampConnector):
 class WampConnector(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         master = yield fakemaster.make_master(self)
         self.connector = TestedWampConnector()
 
@@ -69,6 +69,10 @@ def setUp(self):
         yield master.startService()
         yield self.connector.reconfigServiceWithBuildbotConfig(config)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_reconfig_same_config(self):
         config = FakeConfig({'type': 'wamp', 'router_url': "wss://foo", 'realm': "bb"})
diff --git a/master/buildbot/test/unit/util/test_backoff.py b/master/buildbot/test/unit/util/test_backoff.py
index 6ed49e29b22..c7ea157512a 100644
--- a/master/buildbot/test/unit/util/test_backoff.py
+++ b/master/buildbot/test/unit/util/test_backoff.py
@@ -28,7 +28,11 @@ class TestException(Exception):
 
 class ExponentialBackoffEngineAsyncTests(unittest.TestCase, TestReactorMixin):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
+
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
 
     def test_construct_asserts(self):
         with self.assertRaises(ValueError):
diff --git a/master/buildbot/test/unit/util/test_codebase.py b/master/buildbot/test/unit/util/test_codebase.py
index 1f07353f438..0d0737ca242 100644
--- a/master/buildbot/test/unit/util/test_codebase.py
+++ b/master/buildbot/test/unit/util/test_codebase.py
@@ -42,11 +42,15 @@ class TestAbsoluteSourceStampsMixin(
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantDb=True, wantData=True)
         self.db = self.master.db
         self.object = FakeObject(self.master, self.codebases)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def mkch(self, **kwargs):
         ch = self.makeFakeChange(**kwargs)
diff --git a/master/buildbot/test/unit/util/test_deferwaiter.py b/master/buildbot/test/unit/util/test_deferwaiter.py
index 199df122b6d..f4fc399aa6d 100644
--- a/master/buildbot/test/unit/util/test_deferwaiter.py
+++ b/master/buildbot/test/unit/util/test_deferwaiter.py
@@ -76,7 +76,11 @@ def test_passes_result(self):
 
 class RepeatedActionHandlerTests(unittest.TestCase, TestReactorMixin):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
+
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_does_not_add_action_on_start(self):
@@ -428,7 +432,11 @@ def action():
 
 class NonRepeatedActionHandlerTests(unittest.TestCase, TestReactorMixin):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
+
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_does_not_add_action_on_start(self):
diff --git a/master/buildbot/test/unit/util/test_kubeclientservice.py b/master/buildbot/test/unit/util/test_kubeclientservice.py
index 8ff0a39b2ef..1b9acb3b45a 100644
--- a/master/buildbot/test/unit/util/test_kubeclientservice.py
+++ b/master/buildbot/test/unit/util/test_kubeclientservice.py
@@ -106,7 +106,7 @@ class KubeClientServiceTestKubeHardcodedConfig(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         self._http = yield fakehttpclientservice.HTTPClientService.getService(
             self.master, self, "http://localhost:8001"
@@ -116,6 +116,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     def test_basic(self):
         self.config = kubeclientservice.KubeHardcodedConfig(
diff --git a/master/buildbot/test/unit/util/test_misc.py b/master/buildbot/test/unit/util/test_misc.py
index e654d883c1a..31a6be70dba 100644
--- a/master/buildbot/test/unit/util/test_misc.py
+++ b/master/buildbot/test/unit/util/test_misc.py
@@ -86,9 +86,13 @@ def check_locked(self, arg1, arg2):
 
 class TestCancelAfter(TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.d = defer.Deferred()
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_succeeds(self):
         d = misc.cancelAfter(10, self.d, self.reactor)
         self.assertIdentical(d, self.d)
diff --git a/master/buildbot/test/unit/util/test_poll.py b/master/buildbot/test/unit/util/test_poll.py
index 450e08727d8..4e86c9efa95 100644
--- a/master/buildbot/test/unit/util/test_poll.py
+++ b/master/buildbot/test/unit/util/test_poll.py
@@ -31,7 +31,7 @@ def poll(self):
             raise RuntimeError('oh noes')
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = mock.Mock()
         self.master.reactor = self.reactor
 
@@ -39,9 +39,11 @@ def setUp(self):
         self.calls = 0
         self.fail_after_running = False
 
+    @defer.inlineCallbacks
     def tearDown(self):
         poll.reset_poll_methods()
         self.assertEqual(self.reactor.getDelayedCalls(), [])
+        yield self.tear_down_test_reactor()
 
     def test_call_not_started_does_nothing(self):
         self.reactor.advance(100)
@@ -190,7 +192,7 @@ def poll(self):
             raise RuntimeError('oh noes')
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = mock.Mock()
         self.master.reactor = self.reactor
 
@@ -200,8 +202,10 @@ def setUp(self):
         self.duration = 1
         self.fail_after_running = False
 
+    @defer.inlineCallbacks
     def tearDown(self):
         poll.reset_poll_methods()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_call_when_started_forces_run(self):
diff --git a/master/buildbot/test/unit/util/test_runprocess.py b/master/buildbot/test/unit/util/test_runprocess.py
index 1854c84ab97..c5821373af2 100644
--- a/master/buildbot/test/unit/util/test_runprocess.py
+++ b/master/buildbot/test/unit/util/test_runprocess.py
@@ -37,11 +37,15 @@ class TestRunProcess(TestReactorMixin, LoggingMixin, unittest.TestCase):
     FAKE_PID = 1234
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setUpLogging()
         self.process = None
         self.reactor.spawnProcess = self.fake_spawn_process
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def fake_spawn_process(self, pp, command, args, env, workdir, usePTY=False):
         self.assertIsNone(self.process)
         self.pp = pp
diff --git a/master/buildbot/test/unit/util/test_service.py b/master/buildbot/test/unit/util/test_service.py
index dfc355bad49..e3cc95102e9 100644
--- a/master/buildbot/test/unit/util/test_service.py
+++ b/master/buildbot/test/unit/util/test_service.py
@@ -103,12 +103,13 @@ class DummyService(service.ClusteredBuildbotService):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantDb=True, wantData=True)
         self.svc = self.makeService()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        pass
+        yield self.tear_down_test_reactor()
 
     def makeService(self, attach_to_master=True, name=SVC_NAME, serviceid=SVC_ID):
         svc = self.DummyService(name=name)
diff --git a/master/buildbot/test/unit/util/test_state.py b/master/buildbot/test/unit/util/test_state.py
index c6e55ec7e10..342a80b9861 100644
--- a/master/buildbot/test/unit/util/test_state.py
+++ b/master/buildbot/test/unit/util/test_state.py
@@ -34,10 +34,14 @@ class TestStateMixin(TestReactorMixin, StateTestMixin, unittest.TestCase):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantDb=True)
         self.object = FakeObject(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_getState(self):
         yield self.set_fake_state(self.object, 'fav_color', ['red', 'purple'])
diff --git a/master/buildbot/test/unit/util/test_test_result_submitter.py b/master/buildbot/test/unit/util/test_test_result_submitter.py
index 7d3cc7e6c3c..65d33110be5 100644
--- a/master/buildbot/test/unit/util/test_test_result_submitter.py
+++ b/master/buildbot/test/unit/util/test_test_result_submitter.py
@@ -25,7 +25,7 @@
 class TestTestResultSubmitter(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantData=True, wantDb=True)
         yield self.master.startService()
 
@@ -44,6 +44,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_complete_empty(self):
diff --git a/master/buildbot/test/unit/util/test_watchdog.py b/master/buildbot/test/unit/util/test_watchdog.py
index fa6cd31ae5f..d2eaea5b0b6 100644
--- a/master/buildbot/test/unit/util/test_watchdog.py
+++ b/master/buildbot/test/unit/util/test_watchdog.py
@@ -15,6 +15,7 @@
 
 from unittest import mock
 
+from twisted.internet import defer
 from twisted.trial import unittest
 
 from buildbot.test.reactor import TestReactorMixin
@@ -23,7 +24,11 @@
 
 class TestWatchdog(TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
+
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
 
     def test_not_started_no_calls(self):
         m = mock.Mock()
diff --git a/master/buildbot/test/unit/worker/test_base.py b/master/buildbot/test/unit/worker/test_base.py
index ebe9c2e08a7..dc2abccc1f7 100644
--- a/master/buildbot/test/unit/worker/test_base.py
+++ b/master/buildbot/test/unit/worker/test_base.py
@@ -115,9 +115,13 @@ def canStartBuild(self):
 
 class RealWorkerItfc(TestReactorMixin, unittest.TestCase, WorkerInterfaceTests):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.wrk = ConcreteWorker('wrk', 'pa')
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def callAttached(self):
         self.master = yield fakemaster.make_master(self, wantData=True)
@@ -133,10 +137,14 @@ def callAttached(self):
 class FakeWorkerItfc(TestReactorMixin, unittest.TestCase, WorkerInterfaceTests):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         self.wrk = worker.FakeWorker(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def callAttached(self):
         self.conn = fakeprotocol.FakeConnection(self.wrk)
         return self.wrk.attached(self.conn)
@@ -145,7 +153,7 @@ def callAttached(self):
 class TestAbstractWorker(logging.LoggingMixin, TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setUpLogging()
         self.master = yield fakemaster.make_master(self, wantDb=True, wantData=True)
         self.botmaster = self.master.botmaster
@@ -153,6 +161,10 @@ def setUp(self):
         self.workers = self.master.workers = bworkermanager.FakeWorkerManager()
         yield self.workers.setServiceParent(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def createWorker(self, name='bot', password='pass', attached=False, configured=True, **kwargs):
         worker = ConcreteWorker(name, password, **kwargs)
@@ -916,13 +928,17 @@ def test_worker_quarantine_stop_timer(self):
 class TestAbstractLatentWorker(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantDb=True, wantData=True)
         self.botmaster = self.master.botmaster
         yield self.master.workers.disownServiceParent()
         self.workers = self.master.workers = bworkermanager.FakeWorkerManager()
         yield self.workers.setServiceParent(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def do_test_reconfigService(self, old, new, existingRegistration=True):
         old.parent = self.master
diff --git a/master/buildbot/test/unit/worker/test_docker.py b/master/buildbot/test/unit/worker/test_docker.py
index 1c1cfb41ac0..6a64748e02e 100644
--- a/master/buildbot/test/unit/worker/test_docker.py
+++ b/master/buildbot/test/unit/worker/test_docker.py
@@ -47,7 +47,7 @@ def _create_client(self, *args, **kwargs):
         return self._client
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         self.patch(dockerworker, 'docker', docker)
 
@@ -61,6 +61,10 @@ def setUp(self):
         docker.Client.containerCreated = False
         docker.Client.start_exception = None
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_constructor_noimage_nodockerfile(self):
         with self.assertRaises(config.ConfigErrors):
diff --git a/master/buildbot/test/unit/worker/test_kubernetes.py b/master/buildbot/test/unit/worker/test_kubernetes.py
index 873a66c72ef..2762ef209d3 100644
--- a/master/buildbot/test/unit/worker/test_kubernetes.py
+++ b/master/buildbot/test/unit/worker/test_kubernetes.py
@@ -63,7 +63,7 @@ class TestKubernetesWorker(TestReactorMixin, unittest.TestCase):
     worker = None
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
     @defer.inlineCallbacks
     def setupWorker(self, *args, config=None, **kwargs):
@@ -86,6 +86,10 @@ def setupWorker(self, *args, config=None, **kwargs):
         self.addCleanup(self.master.stopService)
         return worker
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def get_expected_metadata(self):
         return {"name": "buildbot-worker-87de7e"}
 
diff --git a/master/buildbot/test/unit/worker/test_libvirt.py b/master/buildbot/test/unit/worker/test_libvirt.py
index 1c3ed07a7d1..e9bc24a4457 100644
--- a/master/buildbot/test/unit/worker/test_libvirt.py
+++ b/master/buildbot/test/unit/worker/test_libvirt.py
@@ -67,12 +67,16 @@ class TestException(Exception):
 
 class TestLibVirtWorker(TestReactorMixin, MasterRunProcessMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setup_master_run_process()
         self.connections = {}
         self.patch(libvirtworker, "libvirt", libvirtfake)
         self.threadpool = TestServerThreadPool(self)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def libvirt_open(self, uri):
         if uri not in self.connections:
             raise RuntimeError('Could not find test connection')
diff --git a/master/buildbot/test/unit/worker/test_local.py b/master/buildbot/test/unit/worker/test_local.py
index 4aa20222464..fb128729d04 100644
--- a/master/buildbot/test/unit/worker/test_local.py
+++ b/master/buildbot/test/unit/worker/test_local.py
@@ -32,11 +32,15 @@ class TestLocalWorker(TestReactorMixin, unittest.TestCase):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantDb=True, wantData=True)
         self.botmaster = self.master.botmaster
         self.workers = self.master.workers
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def createWorker(self, name='bot', attached=False, configured=True, **kwargs):
         worker = local.LocalWorker(name, **kwargs)
         if configured:
diff --git a/master/buildbot/test/unit/worker/test_manager.py b/master/buildbot/test/unit/worker/test_manager.py
index ca02fbfd246..ef363095ed5 100644
--- a/master/buildbot/test/unit/worker/test_manager.py
+++ b/master/buildbot/test/unit/worker/test_manager.py
@@ -47,7 +47,7 @@ class FakeWorker2(FakeWorker):
 class TestWorkerManager(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantData=True)
         self.master.mq = self.master.mq
         self.workers = workermanager.WorkerManager(self.master)
@@ -61,8 +61,10 @@ def setUp(self):
         self.new_config = mock.Mock()
         self.workers.startService()
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.workers.stopService()
+        yield self.workers.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_reconfigServiceWorkers_add_remove(self):
diff --git a/master/buildbot/test/unit/worker/test_marathon.py b/master/buildbot/test/unit/worker/test_marathon.py
index 6a25b2a80d7..7ba37295f0f 100644
--- a/master/buildbot/test/unit/worker/test_marathon.py
+++ b/master/buildbot/test/unit/worker/test_marathon.py
@@ -29,10 +29,11 @@
 
 class TestMarathonLatentWorker(unittest.TestCase, TestReactorMixin):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.build = Properties(image="busybox:latest", builder="docker_worker")
         self.worker = None
 
+    @defer.inlineCallbacks
     def tearDown(self):
         if self.worker is not None:
 
@@ -40,8 +41,9 @@ class FakeResult:
                 code = 200
 
             self._http.delete = lambda _: defer.succeed(FakeResult())
-            self.worker.master.stopService()
+            yield self.worker.master.stopService()
         self.flushLoggedErrors(LatentWorkerSubstantiatiationCancelled)
+        yield self.tear_down_test_reactor()
 
     def test_constructor_normal(self):
         worker = MarathonLatentWorker('bot', 'tcp://marathon.local', 'foo', 'bar', 'debian:wheezy')
diff --git a/master/buildbot/test/unit/worker/test_openstack.py b/master/buildbot/test/unit/worker/test_openstack.py
index df4d89bd9a3..cf9d65bee8c 100644
--- a/master/buildbot/test/unit/worker/test_openstack.py
+++ b/master/buildbot/test/unit/worker/test_openstack.py
@@ -43,7 +43,7 @@ class TestOpenStackWorker(TestReactorMixin, unittest.TestCase):
     bs_image_args = {"flavor": 1, "image": '28a65eb4-f354-4420-97dc-253b826547f7', **os_auth}
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.patch(openstack, "client", novaclient)
         self.patch(openstack, "loading", novaclient)
         self.patch(openstack, "session", novaclient)
@@ -55,6 +55,10 @@ def setUp(self):
         )
         self.masterhash = hashlib.sha1(b'fake:/master').hexdigest()[:6]
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def setupWorker(self, *args, **kwargs):
         worker = openstack.OpenStackLatentWorker(*args, **kwargs)
diff --git a/master/buildbot/test/unit/worker/test_protocols_base.py b/master/buildbot/test/unit/worker/test_protocols_base.py
index d0b1abe4fb2..1563cac5fa5 100644
--- a/master/buildbot/test/unit/worker/test_protocols_base.py
+++ b/master/buildbot/test/unit/worker/test_protocols_base.py
@@ -15,6 +15,7 @@
 
 from unittest import mock
 
+from twisted.internet import defer
 from twisted.trial import unittest
 
 from buildbot.test.fake import fakeprotocol
@@ -25,17 +26,25 @@
 
 class TestFakeConnection(protocols.ConnectionInterfaceTest, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.worker = mock.Mock()
         self.conn = fakeprotocol.FakeConnection(self.worker)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
 
 class TestConnection(protocols.ConnectionInterfaceTest, TestReactorMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.worker = mock.Mock()
         self.conn = base.Connection(self.worker.workername)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_notify(self):
         cb = mock.Mock()
 
diff --git a/master/buildbot/test/unit/worker/test_protocols_msgpack.py b/master/buildbot/test/unit/worker/test_protocols_msgpack.py
index a35cc7d10b3..f7ffe0d9174 100644
--- a/master/buildbot/test/unit/worker/test_protocols_msgpack.py
+++ b/master/buildbot/test/unit/worker/test_protocols_msgpack.py
@@ -32,9 +32,13 @@
 class TestListener(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_constructor(self):
         listener = msgpack.Listener(self.master)
         self.assertEqual(listener.master, self.master)
@@ -84,21 +88,29 @@ class TestConnectionApi(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         self.conn = msgpack.Connection(self.master, mock.Mock(), mock.Mock())
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
 
 class TestConnection(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         self.protocol = mock.Mock()
         self.worker = mock.Mock()
         self.worker.workername = 'test_worker'
         self.conn = msgpack.Connection(self.master, self.worker, self.protocol)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_constructor(self):
         self.assertEqual(self.conn.protocol, self.protocol)
         self.assertEqual(self.conn.master, self.master)
diff --git a/master/buildbot/test/unit/worker/test_protocols_pb.py b/master/buildbot/test/unit/worker/test_protocols_pb.py
index 64179fc0649..1dca42960cd 100644
--- a/master/buildbot/test/unit/worker/test_protocols_pb.py
+++ b/master/buildbot/test/unit/worker/test_protocols_pb.py
@@ -30,9 +30,13 @@
 class TestListener(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def makeListener(self):
         listener = pb.Listener(self.master)
         return listener
@@ -85,19 +89,27 @@ class TestConnectionApi(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         self.conn = pb.Connection(self.master, mock.Mock(), mock.Mock())
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
 
 class TestConnection(TestReactorMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self)
         self.mind = mock.Mock()
         self.worker = mock.Mock()
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_constructor(self):
         conn = pb.Connection(self.master, self.worker, self.mind)
 
diff --git a/master/buildbot/test/unit/worker/test_upcloud.py b/master/buildbot/test/unit/worker/test_upcloud.py
index 5148a12fa03..e6cd2490475 100644
--- a/master/buildbot/test/unit/worker/test_upcloud.py
+++ b/master/buildbot/test/unit/worker/test_upcloud.py
@@ -81,7 +81,11 @@ class TestUpcloudWorker(TestReactorMixin, unittest.TestCase):
     worker = None
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
+
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def setupWorker(self, *args, **kwargs):
diff --git a/master/buildbot/test/unit/www/test_auth.py b/master/buildbot/test/unit/www/test_auth.py
index 1fc6ed131a9..491f8bb53c9 100644
--- a/master/buildbot/test/unit/www/test_auth.py
+++ b/master/buildbot/test/unit/www/test_auth.py
@@ -42,10 +42,14 @@ def setUpAuthResource(self):
 class AuthRootResource(TestReactorMixin, www.WwwTestMixin, AuthResourceMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpAuthResource()
         self.rsrc = auth.AuthRootResource(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_getChild_login(self):
         glr = mock.Mock(name='glr')
         self.master.www.auth.getLoginResource = glr
@@ -62,12 +66,16 @@ def test_getChild_logout(self):
 class AuthBase(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.auth = auth.AuthBase()
         self.master = yield self.make_master(url='h:/a/b/')
         self.auth.master = self.master
         self.req = self.make_request(b'/')
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_maybeAutoLogin(self):
         self.assertEqual((yield self.auth.maybeAutoLogin(self.req)), None)
@@ -103,11 +111,15 @@ def test_exists(self):
 class RemoteUserAuth(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.auth = auth.RemoteUserAuth(header=b'HDR')
         yield self.make_master()
         self.request = self.make_request(b'/')
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_maybeAutoLogin(self):
         self.request.input_headers[b'HDR'] = b'rachel@foo.com'
@@ -143,11 +155,15 @@ def test_get_login_resource_does_not_throw(self):
 class AuthRealm(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.auth = auth.RemoteUserAuth(header=b'HDR')
         self.auth = auth.NoAuth()
         yield self.make_master()
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_requestAvatar(self):
         realm = auth.AuthRealm(self.master, self.auth)
         itfc, rsrc, _ = realm.requestAvatar("me", None, IResource)
@@ -157,7 +173,7 @@ def test_requestAvatar(self):
 
 class TwistedICredAuthBase(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
     # twisted.web makes it difficult to simulate the authentication process, so
     # this only tests the mechanics of the getLoginResource method.
@@ -192,7 +208,11 @@ def check_credentials(self, us, ps):
             return us == 'fellow' and ps == 'correct'
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
+
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_callable(self):
@@ -208,9 +228,13 @@ def test_callable(self):
 class LoginResource(TestReactorMixin, www.WwwTestMixin, AuthResourceMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpAuthResource()
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_render(self):
         self.rsrc = auth.LoginResource(self.master)
@@ -227,10 +251,14 @@ class PreAuthenticatedLoginResource(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpAuthResource()
         self.rsrc = auth.PreAuthenticatedLoginResource(self.master, 'him')
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_render(self):
         self.auth.maybeAutoLogin = mock.Mock()
@@ -252,10 +280,14 @@ def updateUserInfo(request):
 class LogoutResource(TestReactorMixin, www.WwwTestMixin, AuthResourceMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         yield self.setUpAuthResource()
         self.rsrc = auth.LogoutResource(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_render(self):
         self.master.session.expire = mock.Mock()
diff --git a/master/buildbot/test/unit/www/test_authz.py b/master/buildbot/test/unit/www/test_authz.py
index 46687583f24..481829bfad4 100644
--- a/master/buildbot/test/unit/www/test_authz.py
+++ b/master/buildbot/test/unit/www/test_authz.py
@@ -36,7 +36,7 @@
 class Authz(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         authzcfg = authz.Authz(
             # simple matcher with '*' glob character
             stringsMatcher=authz.fnmatchStrMatcher,
@@ -107,6 +107,10 @@ def setUp(self):
             ),
         ])
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def setAllowRules(self, allow_rules):
         # we should add links to authz and master instances in each new rule
         for r in allow_rules:
diff --git a/master/buildbot/test/unit/www/test_avatar.py b/master/buildbot/test/unit/www/test_avatar.py
index f8467dfeb17..6fb72107764 100644
--- a/master/buildbot/test/unit/www/test_avatar.py
+++ b/master/buildbot/test/unit/www/test_avatar.py
@@ -32,7 +32,11 @@ def getUserAvatar(self, email, username, size, defaultAvatarUrl):
 
 class AvatarResource(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
+
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_default(self):
@@ -530,7 +534,7 @@ def getUserAvatar(self, email, username, size, defaultAvatarUrl):
 class GitHubAvatar(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         master = yield self.make_master(
             url='http://a/b/',
@@ -558,6 +562,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_username(self):
@@ -732,7 +737,7 @@ def test_email_error(self):
 class GitHubAvatarBasicAuth(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         avatar_method = avatar.AvatarGitHub(client_id="oauth_id", client_secret="oauth_secret")
         master = yield self.make_master(
@@ -760,6 +765,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     def test_incomplete_credentials(self):
         with self.assertRaises(config.ConfigErrors):
diff --git a/master/buildbot/test/unit/www/test_config.py b/master/buildbot/test/unit/www/test_config.py
index 68d89baaa1d..a1acc763b46 100644
--- a/master/buildbot/test/unit/www/test_config.py
+++ b/master/buildbot/test/unit/www/test_config.py
@@ -51,7 +51,11 @@ def test_serialize_www_frontend_theme_to_css(self):
 
 class TestConfigResource(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
+
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_render(self):
@@ -84,7 +88,11 @@ def test_render(self):
 
 class IndexResourceTest(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
+
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
 
     def get_react_base_path(self):
         path = os.path.abspath(os.path.dirname(os.path.dirname(__file__)))
diff --git a/master/buildbot/test/unit/www/test_endpointmatchers.py b/master/buildbot/test/unit/www/test_endpointmatchers.py
index 5dbe2e1b9b2..457da4877b7 100644
--- a/master/buildbot/test/unit/www/test_endpointmatchers.py
+++ b/master/buildbot/test/unit/www/test_endpointmatchers.py
@@ -27,13 +27,17 @@
 class EndpointBase(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield self.make_master(url='h:/a/b/')
         self.db = self.master.db
         self.matcher = self.makeMatcher()
         self.matcher.setAuthz(self.master.authz)
         yield self.insertData()
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def makeMatcher(self):
         raise NotImplementedError()
 
diff --git a/master/buildbot/test/unit/www/test_graphql.py b/master/buildbot/test/unit/www/test_graphql.py
index 891ee17926c..ed433cc869a 100644
--- a/master/buildbot/test/unit/www/test_graphql.py
+++ b/master/buildbot/test/unit/www/test_graphql.py
@@ -225,11 +225,15 @@ class DisabledV3RootResource(TestReactorMixin, www.WwwTestMixin, unittest.TestCa
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield self.make_master(url="http://server/path/")
         self.rsrc = graphql.V3RootResource(self.master)
         self.rsrc.reconfigResource(self.master.config)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_basic_disabled(self):
         yield self.render_resource(self.rsrc, b"/")
diff --git a/master/buildbot/test/unit/www/test_hooks_base.py b/master/buildbot/test/unit/www/test_hooks_base.py
index 799541e2b0f..4b551ec8b6f 100644
--- a/master/buildbot/test/unit/www/test_hooks_base.py
+++ b/master/buildbot/test/unit/www/test_hooks_base.py
@@ -39,9 +39,13 @@ def _prepare_request(payload, headers=None):
 class TestChangeHookConfiguredWithBase(unittest.TestCase, TestReactorMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.changeHook = yield _prepare_base_change_hook(self)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def _check_base_with_change(self, payload):
         self.request = _prepare_request(payload)
@@ -98,7 +102,7 @@ def test_base_with_changes(self):
 class TestChangeHookConfiguredWithCustomBase(unittest.TestCase, TestReactorMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         class CustomBase(BaseHookHandler):
             def getChanges(self, request):
@@ -113,6 +117,10 @@ def getChanges(self, request):
 
         self.changeHook = yield _prepare_base_change_hook(self, custom_class=CustomBase)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def _check_base_with_change(self, payload):
         self.request = _prepare_request(payload)
diff --git a/master/buildbot/test/unit/www/test_hooks_bitbucket.py b/master/buildbot/test/unit/www/test_hooks_bitbucket.py
index 396c2a5c9de..779b8568d21 100644
--- a/master/buildbot/test/unit/www/test_hooks_bitbucket.py
+++ b/master/buildbot/test/unit/www/test_hooks_bitbucket.py
@@ -139,12 +139,16 @@ class TestChangeHookConfiguredWithBitbucketChange(unittest.TestCase, TestReactor
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         master = yield fakeMasterForHooks(self)
         self.change_hook = change_hook.ChangeHookResource(
             dialects={'bitbucket': True}, master=master
         )
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def testGitWithChange(self):
         change_dict = {b'payload': [gitJsonPayload]}
diff --git a/master/buildbot/test/unit/www/test_hooks_bitbucketcloud.py b/master/buildbot/test/unit/www/test_hooks_bitbucketcloud.py
index 8727052276b..9f711eb0e53 100644
--- a/master/buildbot/test/unit/www/test_hooks_bitbucketcloud.py
+++ b/master/buildbot/test/unit/www/test_hooks_bitbucketcloud.py
@@ -684,7 +684,7 @@ def _prepare_request(payload, headers=None, change_dict=None):
 class TestChangeHookConfiguredWithGitChange(unittest.TestCase, TestReactorMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         master = yield fakeMasterForHooks(self)
         self.change_hook = change_hook.ChangeHookResource(
             dialects={
@@ -695,6 +695,10 @@ def setUp(self):
             master=master,
         )
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def assertDictSubset(self, expected_dict, response_dict):
         expected = {}
         for key in expected_dict.keys():
diff --git a/master/buildbot/test/unit/www/test_hooks_bitbucketserver.py b/master/buildbot/test/unit/www/test_hooks_bitbucketserver.py
index d72c339b49b..d620f61d89d 100644
--- a/master/buildbot/test/unit/www/test_hooks_bitbucketserver.py
+++ b/master/buildbot/test/unit/www/test_hooks_bitbucketserver.py
@@ -709,7 +709,7 @@ def _prepare_request(payload, headers=None, change_dict=None):
 class TestChangeHookConfiguredWithGitChange(unittest.TestCase, TestReactorMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         master = yield fakeMasterForHooks(self)
         self.change_hook = change_hook.ChangeHookResource(
             dialects={
@@ -720,6 +720,10 @@ def setUp(self):
             master=master,
         )
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def assertDictSubset(self, expected_dict, response_dict):
         expected = {}
         for key in expected_dict.keys():
diff --git a/master/buildbot/test/unit/www/test_hooks_github.py b/master/buildbot/test/unit/www/test_hooks_github.py
index 7c41b325a12..6e5933140d4 100644
--- a/master/buildbot/test/unit/www/test_hooks_github.py
+++ b/master/buildbot/test/unit/www/test_hooks_github.py
@@ -609,7 +609,7 @@ def _prepare_request(event, payload, _secret=None, headers=None):
 class TestChangeHookConfiguredWithGitChange(unittest.TestCase, TestReactorMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.changeHook = yield _prepare_github_change_hook(
             self, strict=False, github_property_whitelist=["github.*"]
         )
@@ -628,6 +628,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     def assertDictSubset(self, expected_dict, response_dict):
         expected = {}
@@ -886,7 +887,7 @@ class TestChangeHookConfiguredWithGitChangeCustomPullrequestRef(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.changeHook = yield _prepare_github_change_hook(
             self, strict=False, github_property_whitelist=["github.*"], pullrequest_ref="head"
         )
@@ -905,6 +906,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_git_pull_request_with_custom_ref(self):
@@ -927,7 +929,7 @@ class TestChangeHookConfiguredWithGitChangeCustomPullrequestRefWithAuth(
 ):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         _token = '7e076f41-b73a-4045-a817'
         self.changeHook = yield _prepare_github_change_hook(
             self,
@@ -954,6 +956,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_git_pull_request_with_custom_ref(self):
@@ -977,7 +980,7 @@ class TestChangeHookRefWithAuth(unittest.TestCase, TestReactorMixin):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         self.changeHook = yield _prepare_github_change_hook(
             self,
@@ -1012,6 +1015,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_git_pull_request(self):
@@ -1030,7 +1034,7 @@ def test_git_pull_request(self):
 class TestChangeHookConfiguredWithAuthAndCustomSkips(unittest.TestCase, TestReactorMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         _token = '7e076f41-b73a-4045-a817'
         self.changeHook = yield _prepare_github_change_hook(
             self, strict=False, skips=[r'\[ *bb *skip *\]'], token=_token
@@ -1053,6 +1057,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def _check_push_with_skip_message(self, payload):
@@ -1121,7 +1126,7 @@ def test_pull_request_no_skip(self):
 class TestChangeHookConfiguredWithAuth(unittest.TestCase, TestReactorMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         _token = '7e076f41-b73a-4045-a817'
         self.changeHook = yield _prepare_github_change_hook(
@@ -1145,6 +1150,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     def assertDictSubset(self, expected_dict, response_dict):
         expected = {}
@@ -1243,7 +1249,7 @@ def test_git_pull_request_with_skip_message(self):
 class TestChangeHookConfiguredWithCustomApiRoot(unittest.TestCase, TestReactorMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.changeHook = yield _prepare_github_change_hook(
             self, strict=False, github_api_endpoint='https://black.magic.io'
         )
@@ -1262,6 +1268,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def _check_pull_request(self, payload):
@@ -1281,7 +1288,7 @@ def test_pull_request(self):
 class TestChangeHookConfiguredWithCustomApiRootWithAuth(unittest.TestCase, TestReactorMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         _token = '7e076f41-b73a-4045-a817'
         self.changeHook = yield _prepare_github_change_hook(
@@ -1305,6 +1312,7 @@ def setUp(self):
     @defer.inlineCallbacks
     def tearDown(self):
         yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def _check_pull_request(self, payload):
@@ -1326,7 +1334,7 @@ class TestChangeHookConfiguredWithStrict(unittest.TestCase, TestReactorMixin):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         fakeStorageService = FakeSecretStorage()
         fakeStorageService.reconfigService(secretdict={"secret_key": self._SECRET})
@@ -1339,6 +1347,10 @@ def setUp(self):
         )
         self.changeHook.master.addService(secretService)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_signature_ok(self):
         self.request = _prepare_request(b'push', gitJsonPayload, _secret=self._SECRET)
@@ -1430,9 +1442,13 @@ def test_signature_missing(self):
 class TestChangeHookConfiguredWithCodebaseValue(unittest.TestCase, TestReactorMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.changeHook = yield _prepare_github_change_hook(self, codebase='foobar')
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def _check_git_with_change(self, payload):
         self.request = _prepare_request(b'push', payload)
@@ -1455,9 +1471,13 @@ def _codebase_function(payload):
 class TestChangeHookConfiguredWithCodebaseFunction(unittest.TestCase, TestReactorMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.changeHook = yield _prepare_github_change_hook(self, codebase=_codebase_function)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def _check_git_with_change(self, payload):
         self.request = _prepare_request(b'push', payload)
@@ -1476,7 +1496,7 @@ def test_git_with_change_json(self):
 class TestChangeHookConfiguredWithCustomEventHandler(unittest.TestCase, TestReactorMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         class CustomGitHubEventHandler(GitHubEventHandler):
             def handle_ping(self, _, __):
@@ -1487,6 +1507,10 @@ def handle_ping(self, _, __):
             self, **{'class': CustomGitHubEventHandler}
         )
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_ping(self):
         self.request = _prepare_request(b'ping', b'{}')
diff --git a/master/buildbot/test/unit/www/test_hooks_gitlab.py b/master/buildbot/test/unit/www/test_hooks_gitlab.py
index 73d1600d43a..2adf7f5c6de 100644
--- a/master/buildbot/test/unit/www/test_hooks_gitlab.py
+++ b/master/buildbot/test/unit/www/test_hooks_gitlab.py
@@ -1019,10 +1019,14 @@ def FakeRequestMR(content):
 class TestChangeHookConfiguredWithGitChange(unittest.TestCase, TestReactorMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         master = yield fakeMasterForHooks(self)
         self.changeHook = change_hook.ChangeHookResource(dialects={'gitlab': True}, master=master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def check_changes_tag_event(self, r, project='', codebase=None):
         self.assertEqual(len(self.changeHook.master.data.updates.changesAdded), 2)
         change = self.changeHook.master.data.updates.changesAdded[0]
@@ -1248,7 +1252,7 @@ class TestChangeHookConfiguredWithSecret(unittest.TestCase, TestReactorMixin):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakeMasterForHooks(self)
 
         fakeStorageService = FakeSecretStorage()
@@ -1262,6 +1266,10 @@ def setUp(self):
             dialects={'gitlab': {'secret': util.Secret("secret_key")}}, master=self.master
         )
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_missing_secret(self):
         self.request = FakeRequest(content=gitJsonPayloadTag)
diff --git a/master/buildbot/test/unit/www/test_hooks_gitorious.py b/master/buildbot/test/unit/www/test_hooks_gitorious.py
index e8c0310646d..f81989f8c1e 100644
--- a/master/buildbot/test/unit/www/test_hooks_gitorious.py
+++ b/master/buildbot/test/unit/www/test_hooks_gitorious.py
@@ -64,11 +64,15 @@
 class TestChangeHookConfiguredWithGitChange(unittest.TestCase, TestReactorMixin):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         dialects = {'gitorious': True}
         master = yield fakeMasterForHooks(self)
         self.changeHook = change_hook.ChangeHookResource(dialects=dialects, master=master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     # Test 'base' hook with attributes. We should get a json string
     # representing a Change object as a dictionary. All values show be set.
     @defer.inlineCallbacks
diff --git a/master/buildbot/test/unit/www/test_hooks_poller.py b/master/buildbot/test/unit/www/test_hooks_poller.py
index 920d733eaed..e54eb884746 100644
--- a/master/buildbot/test/unit/www/test_hooks_poller.py
+++ b/master/buildbot/test/unit/www/test_hooks_poller.py
@@ -35,7 +35,7 @@ def poll(self):
             self.called = True
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
     @defer.inlineCallbacks
     def setUpRequest(self, args, options=True, activate=True):
@@ -66,8 +66,10 @@ def setUpRequest(self, args, options=True, activate=True):
         yield self.request.test_render(self.changeHook)
         yield util.asyncSleep(0.1)
 
+    @defer.inlineCallbacks
     def tearDown(self):
-        return self.master.stopService()
+        yield self.master.stopService()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_no_args(self):
diff --git a/master/buildbot/test/unit/www/test_ldapuserinfo.py b/master/buildbot/test/unit/www/test_ldapuserinfo.py
index b27a95e03b7..56031bf386e 100644
--- a/master/buildbot/test/unit/www/test_ldapuserinfo.py
+++ b/master/buildbot/test/unit/www/test_ldapuserinfo.py
@@ -186,7 +186,7 @@ class LdapAvatar(CommonTestCase, TestReactorMixin, WwwTestMixin):
     @defer.inlineCallbacks
     def setUp(self):
         CommonTestCase.setUp(self)
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         master = yield self.make_master(url='http://a/b/', avatar_methods=[self.userInfoProvider])
 
@@ -195,6 +195,10 @@ def setUp(self):
 
         yield self.master.startService()
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def makeUserInfoProvider(self):
         self.userInfoProvider = ldapuserinfo.LdapUserInfo(
             uri="ldap://uri",
diff --git a/master/buildbot/test/unit/www/test_oauth.py b/master/buildbot/test/unit/www/test_oauth.py
index 3493159d466..053a1a2af32 100644
--- a/master/buildbot/test/unit/www/test_oauth.py
+++ b/master/buildbot/test/unit/www/test_oauth.py
@@ -60,7 +60,7 @@ def raise_for_status(self):
 class OAuth2Auth(TestReactorMixin, www.WwwTestMixin, ConfigErrorsMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         if requests is None:
             raise unittest.SkipTest("Need to install requests to test oauth2")
 
@@ -113,6 +113,10 @@ def setUp(self):
         yield secret_service.setServiceParent(self._master)
         self.githubAuth_secret.reconfigAuth(master, master.config)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_getGoogleLoginURL(self):
         res = yield self.googleAuth.getLoginURL('http://redir')
@@ -553,7 +557,7 @@ def _instantiateAuth(self, cls, config):
 
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         if requests is None:
             raise unittest.SkipTest("Need to install requests to test oauth2")
@@ -584,6 +588,7 @@ def tearDown(self):
         for reader in reactor.getReaders():
             if isinstance(reader, Server):
                 reader.connectionLost(f)
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_E2E(self):
diff --git a/master/buildbot/test/unit/www/test_resource.py b/master/buildbot/test/unit/www/test_resource.py
index b0020ed93b3..15c325d1680 100644
--- a/master/buildbot/test/unit/www/test_resource.py
+++ b/master/buildbot/test/unit/www/test_resource.py
@@ -28,7 +28,11 @@ class ResourceSubclass(resource.Resource):
 
 class Resource(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
+
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_base_url(self):
@@ -45,7 +49,11 @@ def test_reconfigResource_registration(self):
 
 class RedirectResource(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
+
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def test_redirect(self):
diff --git a/master/buildbot/test/unit/www/test_rest.py b/master/buildbot/test/unit/www/test_rest.py
index cfb9ef21e97..adf972f1caf 100644
--- a/master/buildbot/test/unit/www/test_rest.py
+++ b/master/buildbot/test/unit/www/test_rest.py
@@ -37,9 +37,13 @@ class RestRootResource(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     maxVersion = 3
 
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         _ = graphql  # used for import side effect
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     @defer.inlineCallbacks
     def test_render(self):
         master = yield self.make_master(url='h:/a/b/')
@@ -71,12 +75,16 @@ def test_versions_limited(self):
 class V2RootResource(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield self.make_master(url='http://server/path/')
         self.master.data._scanModule(endpoint)
         self.rsrc = rest.V2RootResource(self.master)
         self.rsrc.reconfigResource(self.master.config)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def assertSimpleError(self, message, responseCode):
         content = json.dumps({'error': message})
         self.assertRequest(content=unicode2bytes(content), responseCode=responseCode)
@@ -140,7 +148,7 @@ def test_default_origin(self):
 class V2RootResource_CORS(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield self.make_master(url='h:/')
         self.master.data._scanModule(endpoint)
         self.rsrc = rest.V2RootResource(self.master)
@@ -153,6 +161,10 @@ def renderRest(request):
 
         self.rsrc.renderRest = renderRest
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def assertOk(self, expectHeaders=True, content=b'ok', origin=b'h://good'):
         hdrs = (
             {
@@ -260,7 +272,7 @@ def test_cors_origin_preflight_bad_origin(self):
 class V2RootResource_REST(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield self.make_master(url='h:/')
         self.master.config.www['debug'] = True
         self.master.data._scanModule(endpoint)
@@ -277,6 +289,10 @@ def allow(*args, **kw):
         endpoint.Test.kind = EndpointKind.COLLECTION
         endpoint.Test.rtype = endpoint.Test
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def assertRestCollection(
         self, typeName, items, total=None, contentType=None, orderSignificant=False
     ):
@@ -753,7 +769,7 @@ def assertRestAuthError(self, message, responseCode=400):
 class V2RootResource_JSONRPC2(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield self.make_master(url='h:/')
 
         def allow(*args, **kw):
@@ -765,6 +781,10 @@ def allow(*args, **kw):
         self.rsrc = rest.V2RootResource(self.master)
         self.rsrc.reconfigResource(self.master.config)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def assertJsonRpcError(self, message, responseCode=400, jsonrpccode=None):
         got = {}
         got['contentType'] = self.request.headers[b'content-type']
diff --git a/master/buildbot/test/unit/www/test_service.py b/master/buildbot/test/unit/www/test_service.py
index 249a2c7cb89..2bdd9bbae4a 100644
--- a/master/buildbot/test/unit/www/test_service.py
+++ b/master/buildbot/test/unit/www/test_service.py
@@ -59,11 +59,15 @@ def reconfigResource(self, new_config):
 class Test(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield self.make_master(url='h:/a/b/')
         self.svc = self.master.www = service.WWWService()
         yield self.svc.setServiceParent(self.master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def makeConfig(self, **kwargs):
         w = {"port": None, "auth": auth.NoAuth(), "logfileName": 'l'}
         w.update(kwargs)
diff --git a/master/buildbot/test/unit/www/test_sse.py b/master/buildbot/test/unit/www/test_sse.py
index 02cc0a119f4..d9180bc3c00 100644
--- a/master/buildbot/test/unit/www/test_sse.py
+++ b/master/buildbot/test/unit/www/test_sse.py
@@ -32,10 +32,14 @@
 class EventResource(TestReactorMixin, www.WwwTestMixin, unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = master = yield self.make_master(url=b'h:/a/b/')
         self.sse = sse.EventResource(master)
 
+    @defer.inlineCallbacks
+    def tearDown(self):
+        yield self.tear_down_test_reactor()
+
     def test_simpleapi(self):
         self.render_resource(self.sse, b'/changes/*/*')
         self.readUUID(self.request)
diff --git a/master/buildbot/test/util/connector_component.py b/master/buildbot/test/util/connector_component.py
index 10b1d9eca9b..1935dac1c23 100644
--- a/master/buildbot/test/util/connector_component.py
+++ b/master/buildbot/test/util/connector_component.py
@@ -52,7 +52,7 @@ class ConnectorComponentMixin(TestReactorMixin, db.RealDatabaseMixin):
     @defer.inlineCallbacks
     def setUpConnectorComponent(self, table_names=None, basedir='basedir', dialect_name='sqlite'):
         """Set up C{self.db}, using the given db_url and basedir."""
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
 
         if table_names is None:
             table_names = []
@@ -74,6 +74,7 @@ def tearDownConnectorComponent(self):
         del self.db.pool
         del self.db.model
         del self.db
+        yield self.tear_down_test_reactor()
 
 
 class FakeConnectorComponentMixin(TestReactorMixin):
@@ -81,8 +82,12 @@ class FakeConnectorComponentMixin(TestReactorMixin):
 
     @defer.inlineCallbacks
     def setUpConnectorComponent(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantDb=True)
         self.db = self.master.db
         self.db.checkForeignKeys = True
         self.insert_test_data = self.db.insert_test_data
+
+    @defer.inlineCallbacks
+    def tearDownConnectorComponent(self):
+        yield self.tear_down_test_reactor()
diff --git a/master/buildbot/test/util/endpoint.py b/master/buildbot/test/util/endpoint.py
index 0b3c822b7b1..707b08fb1a1 100644
--- a/master/buildbot/test/util/endpoint.py
+++ b/master/buildbot/test/util/endpoint.py
@@ -38,7 +38,7 @@ class EndpointMixin(TestReactorMixin, interfaces.InterfaceTests):
 
     @defer.inlineCallbacks
     def setUpEndpoint(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.master = yield fakemaster.make_master(self, wantMq=True, wantDb=True, wantData=True)
         self.db = self.master.db
         self.mq = self.master.mq
@@ -68,8 +68,9 @@ def setUpEndpoint(self):
             if pp is not None
         ]
 
+    @defer.inlineCallbacks
     def tearDownEndpoint(self):
-        pass
+        yield self.tear_down_test_reactor()
 
     def validateData(self, object):
         validation.verifyData(self, self.rtype.entityType, {}, object)
diff --git a/master/buildbot/test/util/integration.py b/master/buildbot/test/util/integration.py
index 74e5c092b07..ed7a5bca3e6 100644
--- a/master/buildbot/test/util/integration.py
+++ b/master/buildbot/test/util/integration.py
@@ -85,11 +85,13 @@ def getMaster(case, reactor, config_dict):
 
 class RunFakeMasterTestCase(unittest.TestCase, TestReactorMixin, DebugIntegrationLogsMixin):
     def setUp(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.setupDebugIntegrationLogs()
 
+    @defer.inlineCallbacks
     def tearDown(self):
         self.assertFalse(self.master.running, "master is still running!")
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def setup_master(self, config_dict):
diff --git a/master/buildbot/test/util/migration.py b/master/buildbot/test/util/migration.py
index 7be51c67081..cc979034282 100644
--- a/master/buildbot/test/util/migration.py
+++ b/master/buildbot/test/util/migration.py
@@ -46,7 +46,7 @@
 class MigrateTestMixin(TestReactorMixin, db.RealDatabaseMixin, dirs.DirsMixin):
     @defer.inlineCallbacks
     def setUpMigrateTest(self):
-        self.setup_test_reactor()
+        self.setup_test_reactor(auto_tear_down=False)
         self.basedir = os.path.abspath("basedir")
         self.setUpDirs('basedir')
 
@@ -57,9 +57,11 @@ def setUpMigrateTest(self):
         yield self.db.setServiceParent(master)
         self.db.pool = self.db_pool
 
+    @defer.inlineCallbacks
     def tearDownMigrateTest(self):
         self.tearDownDirs()
-        return self.tearDownRealDatabase()
+        yield self.tearDownRealDatabase()
+        yield self.tear_down_test_reactor()
 
     @defer.inlineCallbacks
     def do_test_migration(self, base_revision, target_revision, setup_thd_cb, verify_thd_cb):
diff --git a/master/docs/manual/configuration/tests/reactor.rst b/master/docs/manual/configuration/tests/reactor.rst
index c38831286a4..279183b831b 100644
--- a/master/docs/manual/configuration/tests/reactor.rst
+++ b/master/docs/manual/configuration/tests/reactor.rst
@@ -15,8 +15,17 @@ TestReactorMixin
 
     For more information see the documentation of `twisted.internet.task.Clock <https://twistedmatrix.com/documents/current/api/twisted.internet.task.Clock.html>`_.
 
-    .. py:method:: setup_test_reactor(use_asyncio=False)
+    .. py:method:: setup_test_reactor(use_asyncio=False, auto_tear_down=True)
 
-        :param bool use_asyncio Whether to enable asyncio integration.
+        :param bool use_asyncio: Whether to enable asyncio integration.
+        :param bool auto_tear_down: Whether to automatically tear down the test reactor. This
+            option is deprecated in favor of ``tear_down_test_reactor()`` as the automatic tear
+            down can only run before ``tearDown()`` and thus in many tests the test reactor is
+            shut down prematurely.
 
         Call this function in the ``setUp()`` of the test case to setup fake reactor.
+
+    .. py:method:: tear_down_test_reactor()
+
+        Call this function in the ``tearDown()`` of the test case to tear down fake reactor.
+        The function returns a ``Deferred``.
diff --git a/master/docs/manual/configuration/tests/steps.rst b/master/docs/manual/configuration/tests/steps.rst
index ba9bfddb341..74405982a88 100644
--- a/master/docs/manual/configuration/tests/steps.rst
+++ b/master/docs/manual/configuration/tests/steps.rst
@@ -16,12 +16,15 @@ TestBuildStepMixin
 
         class RemovePYCs(TestBuildStepMixin, TestReactorMixin, unittest.TestCase):
 
+            @defer.inlineCallbacks
             def setUp(self):
-                self.setup_test_reactor()
-                return self.setup_test_build_step()
+                yield self.setup_test_reactor(auto_tear_down=False)
+                yield self.setup_test_build_step()
 
+            @defer.inlineCallbacks
             def tearDown(self):
-                return self.tear_down_test_build_step()
+                yield self.tear_down_test_build_step()
+                yield self.tear_down_test_reactor()
 
             @defer.inlineCallbacks
             def test_run_ok(self):
@@ -32,7 +35,7 @@ TestBuildStepMixin
                     .exit(0)
                 )
                 self.expect_outcome(result=SUCCESS, state_string='remove .pycs')
-                return self.run_step()
+                yield self.run_step()
 
     Basic workflow is as follows:
 
diff --git a/newsfragments/teast-reactor-mixin-explicit-tear-down.feature b/newsfragments/teast-reactor-mixin-explicit-tear-down.feature
new file mode 100644
index 00000000000..f6442ac58dc
--- /dev/null
+++ b/newsfragments/teast-reactor-mixin-explicit-tear-down.feature
@@ -0,0 +1 @@
+Added a way to setup ``TestReactorMixin`` with explicit tear down function.