Python-mock: how to test if super() was called

Question

I have the following structure:

class A(Object):
    def method(self):
        return 'a'

class B(A):
   def __init__(self, test):
       self.test = test

   def method(self):
        if self.test:
           return super(A, self).method(self)
        else:
           return 'b'

What I want to do is write a test-case which would test that if self.test is true then the super function was called and class A's method function was called.

How I can achieve this? What should I mock?

Advanced Q: What about when Class A and B are in a separate module, and they have the same name. So instead of class B I would write: class A(module1.A): does that change the mocking?

Answer 1

As @MartijnPieters points out, testing that super is called is typically a test of an implementation detail, rather than a test of a contract. Nonetheless, testing the specific implementation may still be desirable -- or the parent class may have a contract requiring the call to super. To test that super is called, use a mock, as mentioned by @mgilson. The answer in detail:

import mock, unittest

class TestB(unittest.TestCase):

    @mock.patch("A.method")
    def test_super_method(self, mock_super):
        B(True).method()
        self.assertTrue(mock_super.called)

    @mock.patch("A.method")
    def test_super_method(self, mock_super):
        B(False).method()
        self.assertFalse(mock_super.called)

You'll need to specify the full namespace in the patch. E.g., @mock.patch("module.submodule.A.method"). This can be done for any method in A, including __init__; syntax is exactly the same.