Using assertIsNone() instead of assertEqual(None)

Change-Id: Id5e0e3f0524f62e365f840a7c66c2440ae76959f

trove_dashboard/content/databases/tests.py

@@ -597,7 +597,7 @@ class DatabaseTests(test.TestCase):
         table.maybe_handle()
 
         self.assertEqual(table.data[0].enabled, True)
-        self.assertEqual(table.data[0].password, None)
+        self.assertIsNone(table.data[0].password)
 
     @test.create_stubs({api.trove: ('root_disable',)})
     def test_disable_root_exception(self):