diff --git a/heatclient/tests/unit/test_utils.py b/heatclient/tests/unit/test_utils.py
index 34918162..0cb1462d 100644
--- a/heatclient/tests/unit/test_utils.py
+++ b/heatclient/tests/unit/test_utils.py
@@ -415,8 +415,7 @@ class TestURLFunctions(testtools.TestCase):
                          tmpl_url)
         self.assertEqual(utils.get_template_url(None, tmpl_url),
                          tmpl_url)
-        self.assertEqual(utils.get_template_url(None, None),
-                         None)
+        self.assertIsNone(utils.get_template_url(None, None))
 
     def test_base_url_for_url(self):
         self.assertEqual(
diff --git a/tox.ini b/tox.ini
index 8b6026ba..4ac50ea7 100644
--- a/tox.ini
+++ b/tox.ini
@@ -49,6 +49,7 @@ commands=
 
 [flake8]
 show-source = True
+enable-extensions = H203,H106
 exclude=.venv,.git,.tox,dist,*lib/python*,*egg,build
 max-complexity=20