Tests pass. So, clearly it doesn't need the django test class. 

The difference between `unittest.TestCase` and `django.test.TestCase` is that the latter contains a bunch of cool features that we don't need. 
https://github.com/django/django/blob/1.4.11/django/test/testcases.py#L799

Since this test class (here in test_helpers.py) doesn't use things like `self.client.get`, `self.settings` or doing anything with the ORM (which would mean you'd want django to clean that up) I think we can make the whole test faster if we use the more plain and simple one. 

There is another class we could use too. [SimpleTestCase](https://github.com/django/django/blob/1.4.11/django/test/testcases.py#L328) which only really adds the `self.settings` feature. 

Having said that, I think we should be using `django.utils.unittest.TestCase` instead of `unittest.TestCase` for these simpler test classes.  That gives use backported [unittest2 features](http://www.voidspace.org.uk/python/articles/unittest2.shtml).