Question

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:
        #...

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

Answer 1

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()

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.

Hope this helps someone 🙂