def assertIsNone(self, obj, msg=None):
        if obj is not None:
            standardMsg = '%s is not None' % (safe_repr(obj),)
            self.fail(self._formatMessage(msg, standardMsg))
Same as self.assertTrue(obj is None), with a nicer default message.
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.3/django/utils/unittest/case.py/TestCase.assertIsNone