diff --git a/coriolisclient/tests/cli/test_diagnostics.py b/coriolisclient/tests/cli/test_diagnostics.py
index 46d26c1..ba79c12 100644
--- a/coriolisclient/tests/cli/test_diagnostics.py
+++ b/coriolisclient/tests/cli/test_diagnostics.py
@@ -60,7 +60,8 @@ class GetCoriolisDiagnosticsTestCase(test_base.CoriolisBaseTestCase):
     def setUp(self, mock__init__):
         mock__init__.return_value = None
         super(GetCoriolisDiagnosticsTestCase, self).setUp()
-        self.diag = diagnostics.GetCoriolisDiagnostics()
+        self.diag = diagnostics.GetCoriolisDiagnostics(
+            mock.sentinel.app, mock.sentinel.app_args)
 
     @mock.patch.object(lister.Lister, 'get_parser')
     def test_get_parser(self, mock_get_parser):
diff --git a/coriolisclient/tests/test_base.py b/coriolisclient/tests/test_base.py
index af448cc..7c8c9b1 100644
--- a/coriolisclient/tests/test_base.py
+++ b/coriolisclient/tests/test_base.py
@@ -4,6 +4,13 @@
 """Defines base class for all tests."""
 
 from oslotest import base
+from oslotest import mock_fixture
+
+# NOTE(claudiub): this needs to be called before any mock.patch calls are
+# being done, and especially before any other test classes load. This fixes
+# the mock.patch autospec issue:
+# https://github.com/testing-cabal/mock/issues/396
+mock_fixture.patch_mock_module()
 
 
 class CoriolisBaseTestCase(base.BaseTestCase):