問(wèn)題描述

from mock import Mock
j = []
u = Mock()
u(j)
# At this point u.call_args_list == [call([])]
print u.call_args_list
j.append(100)
# At this point u.call_args_list == [call([100])], but I expect it to be [call([])], since it was never called when j had a value of 100 in it
print u.call_args_list

我的問(wèn)題是如何確保 u.call_args_list 中的調(diào)用在調(diào)用模擬時(shí)而不是在檢查模擬參數(shù)時(shí)包含所有對(duì)象的狀態(tài)?

My question is how do I ensure that the calls in u.call_args_list contain the states of all objects at the time of calling the mock rather than at the time of checking the arguments of the mock?

我目前正在使用 mock==1.0.1.

推薦答案

這在文檔部分進(jìn)行了討論 26.6.3.7.處理可變參數(shù).

This is discussed in the documentation section 26.6.3.7. Coping with mutable arguments.

不幸的是，他們對(duì)這個(gè)問(wèn)題并沒(méi)有任何優(yōu)雅的解決方案！推薦的解決方法是使用 side_effect 從可變參數(shù)中復(fù)制元素.

Unfortunately, they don't really have any elegant solution to the issue! The recommended workaround is copying elements from the mutable arguments by using side_effect.

如果您為模擬提供了一個(gè) side_effect 函數(shù)，那么將使用與模擬相同的參數(shù)調(diào)用 side_effect.這使我們有機(jī)會(huì)復(fù)制參數(shù)并將它們存儲(chǔ)起來(lái)以供以后斷言.

If you provide a side_effect function for a mock then side_effect will be called with the same args as the mock. This gives us an opportunity to copy the arguments and store them for later assertions.

在我看來(lái)，實(shí)施起來(lái)有些混亂.如果您在多個(gè)地方需要該功能，您可能更愿意繼承 Mock 并直接添加該功能:

It's somewhat messy to implement, in my opinion. If you need the capability in multiple places, you may prefer to subclass Mock and add the feature directly:

from copy import deepcopy

class CopyingMock(MagicMock):
    def __call__(self, *args, **kwargs):
        args = deepcopy(args)
        kwargs = deepcopy(kwargs)
        return super(CopyingMock, self).__call__(*args, **kwargs)

<小時(shí)>

2017:它現(xiàn)在可以在第三方發(fā)行版中使用(pip install copyingmock).

2017: It's now available in a third-party distribution (pip install copyingmock).

>>> from copyingmock import CopyingMock
>>> mock = CopyingMock()
>>> list_ = [1,2]
>>> mock(list_)
<CopyingMock name='mock()' id='4366094008'>
>>> list_.append(3)
>>> mock.assert_called_once_with([1,2])
>>> mock.assert_called_once_with(list_)

AssertionError: Expected call: mock([1, 2, 3])
Actual call: mock([1, 2])

這篇關(guān)于我們?nèi)绾未_保 Mock.call_args_list 中的調(diào)用包含具有與調(diào)用 Mock 對(duì)象時(shí)相同狀態(tài)的參數(shù)的調(diào)用?的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！