def test_get_interval_if_no_values(self):
        model = PrimeNumberViewModel()
        model.perform()

        self.assertEqual('', model.get_interval_label())
    def test_get_interval(self):
        model = PrimeNumberViewModel(1, 10)
        model.perform()

        self.assertEqual('range(1, 10)', model.get_interval_label())