diff --git a/tests/test_future.py b/tests/test_future.py
index d023df7f..fe4344e4 100644
--- a/tests/test_future.py
+++ b/tests/test_future.py
@@ -48,7 +48,7 @@ def callback(future):
             def submit():
                 # Executor only exists in this scope and can get garbage collected after
                 # this function is exits
-                future = PyMPISingleTaskExecutor().submit(slow_callable)
+                future = PyMPISingleTaskExecutor(hostname_localhost=True).submit(slow_callable)
                 future.add_done_callback(callback)
                 return future
 
diff --git a/tests/test_meta.py b/tests/test_meta.py
index 7f63e5eb..4efd4d9b 100644
--- a/tests/test_meta.py
+++ b/tests/test_meta.py
@@ -114,6 +114,6 @@ def test_meta_executor_parallel(self):
 
     def test_errors(self):
         with self.assertRaises(TypeError):
-            PyMPIExecutor(max_workers=1, cores_per_worker=1, threads_per_core=2)
+            PyMPIExecutor(max_workers=1, cores_per_worker=1, threads_per_core=2, hostname_localhost=True)
         with self.assertRaises(TypeError):
-            PyMPIExecutor(max_workers=1, cores_per_worker=1, gpus_per_worker=1)
+            PyMPIExecutor(max_workers=1, cores_per_worker=1, gpus_per_worker=1, hostname_localhost=True)