python - 模拟 Python 属性的函数

Question

我这里有:

class Authentication(MethodView):

    @staticmethod
    def make_payload(identity):
        iat = datetime.utcnow()
        exp = iat + timedelta(seconds=300)
        nbf = iat + timedelta(seconds=0)
        identity = identity.key.urlsafe()
        return {'exp': exp, 'iat': iat, 'nbf': nbf, 'identity': identity}

这是基于 JWT 的。我想模拟 identity.key.urlsafe() 以返回 1 这是一个用户 ID:

def test_make_payload(self):
    def get_urlsafe():
        return self.user_id

    now = datetime.utcnow()
    mock_identity = MagicMock()
    mock_identity.key.return_value = MagicMock(urlsafe=get_urlsafe)
    payload = Authentication.make_payload(mock_identity)

现在，除了我的模拟之外，一切正常。目标是返回 1:

ipdb> payload
{'identity': <MagicMock name='mock.key.urlsafe()' id='4392456656'>, 'iat': datetime.datetime(2016, 11, 22, 21, 34, 41, 605698), 'nbf': datetime.datetime(2016, 11, 22, 21, 34, 41, 605698), 'exp': datetime.datetime(2016, 11, 22, 21, 39, 41, 605698)}
ipdb> payload['identity']
<MagicMock name='mock.key.urlsafe()' id='4392456656'>

如何模拟此嵌套调用以使 urlsafe 在模拟中返回 1？

Answer 1

在我看来，您想将模拟的 side_effect 设置为 get_urlsafe:

def test_make_payload(self):
    def get_urlsafe():
        return self.user_id

    now = datetime.utcnow()
    mock_identity = MagicMock()
    mock_identity.key.urlsafe.side_effect = get_urlsafe
    payload = Authentication.make_payload(mock_identity)

来自documentation :

side_effect: A function to be called whenever the Mock is called. See the side_effect attribute. Useful for raising exceptions or dynamically changing return values. The function is called with the same arguments as the mock, and unless it returns DEFAULT, the return value of this function is used as the return value.