Overwriting user_agent in storage/datastore connection tests.

This prevents unnecessary HTTP requests to determine if GCE
is the current environment.

Also updating Test__UserAgentReifyProperty with
- setUp and tearDown to make sure a fresh _UserAgentReifyProperty is
  associated with the Connection class in every test case
- test___get___access_twice test case added to test the branches in
  __get__ for pre-cache and post-cache states

Author: dhermes

gcloud/datastore/test_connection.py

@@ -36,7 +36,10 @@ def _make_query_pb(self, kind):
         return pb
 
     def _makeOne(self, *args, **kw):
-        return self._getTargetClass()(*args, **kw)
+        conn = self._getTargetClass()(*args, **kw)
+        # Set the user agent so the user_agent is not lazily loaded.
+        setattr(conn, 'user_agent', 'gcloud-python/test')
+        return conn
 
     def _verifyProtobufCall(self, called_with, URI, conn):
         self.assertEqual(called_with['uri'], URI)

gcloud/storage/test_connection.py

@@ -22,7 +22,10 @@ def _getTargetClass(self):
         return Connection
 
     def _makeOne(self, *args, **kw):
-        return self._getTargetClass()(*args, **kw)
+        conn = self._getTargetClass()(*args, **kw)
+        # Set the user agent so the user_agent is not lazily loaded.
+        setattr(conn, 'user_agent', 'gcloud-python/test')
+        return conn
 
     def test_ctor_defaults(self):
         PROJECT = 'project'

gcloud/test___init__.py

@@ -17,6 +17,15 @@
 
 class Test__UserAgentReifyProperty(unittest2.TestCase):
 
+    def setUp(self):
+        from gcloud.connection import Connection
+        self._original_connection_user_agent = Connection.user_agent
+        Connection.user_agent = self._makeOne(_NamedObject('user_agent'))
+
+    def tearDown(self):
+        from gcloud.connection import Connection
+        Connection.user_agent = self._original_connection_user_agent
+
     def _getTargetClass(self):
         from gcloud import _UserAgentReifyProperty
         return _UserAgentReifyProperty
@@ -25,8 +34,8 @@ def _makeOne(self, *args, **kw):
         return self._getTargetClass()(*args, **kw)
 
     def test_ctor_defaults(self):
-        ua_prop = self._makeOne(NamedObject())
-        self.assertEqual(ua_prop._property_name, NamedObject.NAME_VAL)
+        ua_prop = self._makeOne(_NamedObject())
+        self.assertEqual(ua_prop._property_name, _NamedObject.NAME_VAL)
         self.assertEqual(ua_prop._curr_environ, None)
         self.assertEqual(ua_prop._user_agent, None)
 
@@ -36,8 +45,8 @@ def test_ctor_appengine_loaded(self):
 
         NON_NULL = object()
         with _Monkey(gcloud, appengine=NON_NULL):
-            ua_prop = self._makeOne(NamedObject())
-        self.assertEqual(ua_prop._property_name, NamedObject.NAME_VAL)
+            ua_prop = self._makeOne(_NamedObject())
+        self.assertEqual(ua_prop._property_name, _NamedObject.NAME_VAL)
         self.assertEqual(ua_prop._curr_environ, '-GAE')
         self.assertEqual(ua_prop._user_agent, None)
 
@@ -100,14 +109,29 @@ def test_instance_property_on_connection_default(self):
         expected_ua = 'gcloud-python/{0}'.format(gcloud.__version__)
         self.assertEqual(cnxn.user_agent, expected_ua)
 
+    def test___get___access_twice(self):
+        import gcloud
+        from gcloud.connection import Connection
+
+        expected_ua = 'gcloud-python/{0}'.format(gcloud.__version__)
+
+        self.assertEqual(Connection.user_agent._user_agent, None)
+        value = Connection.user_agent.__get__(_NamedObject())
+        self.assertEqual(value, expected_ua)
+
+        # Now test using it a second time.
+        self.assertEqual(Connection.user_agent._user_agent, expected_ua)
+        value_again = Connection.user_agent.__get__(_NamedObject())
+        self.assertEqual(value_again, expected_ua)
+
     def test_instance_property_connection_with_appengine(self):
         import gcloud
         from gcloud._testing import _Monkey
         from gcloud.connection import Connection
 
         NON_NULL = object()
         with _Monkey(gcloud, appengine=NON_NULL):
-            local_prop = self._makeOne(NamedObject('user_agent'))
+            local_prop = self._makeOne(_NamedObject('user_agent'))
             with _Monkey(Connection, user_agent=local_prop):
                 cnxn = Connection()
                 value = cnxn.user_agent
@@ -130,7 +154,7 @@ def _factory(host, timeout):
             return CONNECTION
 
         with _Monkey(gcloud, HTTPConnection=_factory):
-            local_prop = self._makeOne(NamedObject('user_agent'))
+            local_prop = self._makeOne(_NamedObject('user_agent'))
             with _Monkey(Connection, user_agent=local_prop):
                 cnxn = Connection()
                 value = cnxn.user_agent
@@ -139,7 +163,7 @@ def _factory(host, timeout):
         self.assertEqual(value, expected_ua)
 
 
-class NamedObject(object):
+class _NamedObject(object):
 
     NAME_VAL = object()