Mocking the super class calls on python

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

Using unittest.mock from the standard library I would do something like this.

In your class definition:

from somelib import ASuperClass  class MyClass(ASuperClass):     def my_cool_method(self):         return super().my_cool_method() 

In the module where you are calling MyClass:

from unittest.mock import patch from mymodule import MyClass  @patch("mypackage.mymodule.ASuperClass.my_cool_method") def call_with_mock(mocked_super):     myinstance = MyClass()     myinstance.my_cool_method()     # do stuff with `mocked_super`  call_with_mock() 

Answer 2

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 :)