def today(cls):
    return cls(2011, 7, 3)
datetime.date = FakeDate


class TestDayOfWeek(TestCase):
    """Test the day of the week functions."""

def test_valid_my_next_day_of_week_sameday(self):
    new_day_of_week = DayOfWeek.objects.create()
new_day_of_week.day = 'SU'
self.assertEqual(new_day_of_week.my_next_day_of_week(), date(2011, 7, 3))
Как использовать насмешку для проверки функции next_day_of_week