python - 模拟 side_effect 迭代器用完后可以重置吗？

Question

mock.reset_mock() 不会重置副作用迭代器。有没有一种方法可以做到这一点而无需再次创建模拟？

>>> from mock import MagicMock
>>> mock = MagicMock(side_effect = [1,2])
>>> mock(), mock()
(1, 2)
>>> mock()

Traceback (most recent call last):
  File "<pyshell#114>", line 1, in <module>
    mock()
  File "C:\Python27\Lib\site-packages\mock.py", line 955, in __call__
    return _mock_self._mock_call(*args, **kwargs)
  File "C:\Python27\Lib\site-packages\mock.py", line 1013, in _mock_call
    result = next(effect)
StopIteration
>>> mock.reset_mock()
>>> mock()

Traceback (most recent call last):
  ...
StopIteration
>>> mock = MagicMock(side_effect = [1,2])
>>> mock(), mock()
(1, 2)
>>> 

目的是在后续测试中重新使用模拟，但我怀疑它不能像生成器一样重新启动。

所以(迟到总比不到好)在被指向正确的方向后，我查看了 mock.py 并发现 side_effect 是一个迭代器对象(不能是 < em>重置一旦耗尽):

def __set_side_effect(self, value):
    value = _try_iter(value)
    ...

def _try_iter(obj):
    ...
    try:
        return iter(obj)
    except TypeError:
        # XXXX backwards compatibility
        # but this will blow up on first call - so maybe we should fail early?
        return obj

和def reset_mock() 没有解决副作用。

Answer 1

正如 user2357112 评论的那样，重新分配 side_effect 将解决您的问题。

>>> from mock import MagicMock
>>>
>>> lst = [1, 2]
>>> mock = MagicMock(side_effect=lst)
>>> mock(), mock()
(1, 2)
>>> mock.side_effect = lst  # <-------
>>> mock(), mock()
(1, 2)