def test_checkers_are_called(self):
        upgrader = UpgradeManager(**self.default_args())
        checkers_mock = upgrader._checkers
        upgrader.before_upgrade()

        for checker_mock in checkers_mock:
            self.called_once(checker_mock.check)
    def test_before_upgrade_is_called(self):
        upgrader = UpgradeManager(**self.default_args())
        upgrader.before_upgrade = mock.Mock()
        upgrader.run()

        self.called_once(upgrader.before_upgrade)