tests.py

    def setUp(self):
        _exists = False
        for _model in apps.get_models():
            if getattr(_model, '_test_eggs', False):
                _exists = True
                self.Eggs = _model

            if getattr(_model, '_test_spam', False):
                _exists = True
                self.Spam = _model

        # Check whether the models exist, and short circuit, if so
        if _exists:
            return

        class Eggs(AccountModel):
            _test_eggs = True  # To denote that this is a test model
            pass

        class Spam(AccountModel):
            _test_spam = True  # To denote that this is a test model
            eggs = models.ForeignKey(Eggs)
            ham = models.CharField(max_length=255)
            chicken = models.CharField(max_length=255)
            steak = models.CharField(_(u'verbose steak'), max_length=255)

        self.Eggs = Eggs
        self.Spam = Spam