在 python 上模拟超类调用

2022-01-08 00:00:00 python mocking unit-testing

问题描述

我正在做一些单元测试，在某些时候我需要模拟一个 super 调用来引发错误，例如:

I am doing some unit testing and at some point I need to mock a super call to throw an error, for example:

@classmethod
def myfunc(cls, *args, **kwargs)
    try:
        super(MyClass, cls).my_function(args, kwargs)
    except MyException as e:
        #...

我正在使用 mocker 库来模拟我的对象，但我还没有找到模拟这个的方法.

I am using the mocker library to mock my objects in general but I haven't found a way to mock this.

解决方案

我找到了一种方法，有点 hacky 但它有效，我会用我的例子来解释，这是基于 这个响应非常感谢@kindall:

I found a way, sort of hacky but it works, I'll explain with my example, this is based on this response so thanks @kindall:

def my_test(self):
    import __builtin__
    from mocker import Mocker, KWARGS, ARGS

    mymocker = mocker.mock()
    mymocker.my_function(ARGS, KWARGS)
    mocker.throw(MyException)

    def mysuper(*args, **kwargs):
        if args and issubclass(MyClass, args[0]):
            return mymocker
        return original_super(*args, **kwargs)

    __builtin__.original_super = super
    __builtin__.super = mysuper

    with mocker:
        MyClass.myfunc()

所以基本上我要做的是检查 super 调用是否来自我要模拟的类，否则只需执行普通的 super.

so essentially what I do is check if the super call is from the class I want to mock, else just do a normal super.

希望这可以帮助某人:)

Hope this helps someone :)

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