Mixins for tests confuse pylint no end, and aren't necessary... you can stop the base-class from being run as a test by prefixing the class name with an underscore

nova/tests/api/openstack/test_images.py

@@ -43,9 +43,14 @@ from nova.tests.api.openstack import fakes
 FLAGS = flags.FLAGS
 
 
-class BaseImageServiceTests(object):
+class _BaseImageServiceTests(test.TestCase):
     """Tasks to test for all image services"""
 
+    def __init__(self, *args, **kwargs):
+        super(_BaseImageServiceTests, self).__init__(*args, **kwargs)
+        self.service = None
+        self.context = None
+
     def test_create(self):
         fixture = self._make_fixture('test image')
         num_images = len(self.service.index(self.context))
@@ -116,8 +121,7 @@ class BaseImageServiceTests(object):
         return fixture
 
 
-class LocalImageServiceTest(test.TestCase,
-                            BaseImageServiceTests):
+class LocalImageServiceTest(_BaseImageServiceTests):
 
     """Tests the local image service"""
 
@@ -147,8 +151,7 @@ class LocalImageServiceTest(test.TestCase,
         self.assertEqual(3, len(found_image_ids), len(found_image_ids))
 
 
-class GlanceImageServiceTest(test.TestCase,
-                             BaseImageServiceTests):
+class GlanceImageServiceTest(_BaseImageServiceTests):
 
     """Tests the Glance image service, in particular that metadata translation
     works properly.

nova/tests/test_auth.py

@@ -80,10 +80,10 @@ class user_and_project_generator(object):
         self.manager.delete_project(self.project)
 
 
-class AuthManagerTestCase(object):
+class _AuthManagerBaseTestCase(test.TestCase):
     def setUp(self):
         FLAGS.auth_driver = self.auth_driver
-        super(AuthManagerTestCase, self).setUp()
+        super(_AuthManagerBaseTestCase, self).setUp()
         self.flags(connection_type='fake')
         self.manager = manager.AuthManager(new=True)
 
@@ -331,11 +331,11 @@ class AuthManagerTestCase(object):
             self.assertTrue(user.is_admin())
 
 
-class AuthManagerLdapTestCase(AuthManagerTestCase, test.TestCase):
+class AuthManagerLdapTestCase(_AuthManagerBaseTestCase):
     auth_driver = 'nova.auth.ldapdriver.FakeLdapDriver'
 
 
-class AuthManagerDbTestCase(AuthManagerTestCase, test.TestCase):
+class AuthManagerDbTestCase(_AuthManagerBaseTestCase):
     auth_driver = 'nova.auth.dbdriver.DbDriver'