Python unittest `setUp` inheritance

README.md

In some cases for Python unit tests, we want to automatically perform setUp methods in as declared in a base class. However, we still want setUp to work as per normal in the subclass. The following code will proxy the new setUp function to run it's base class' and the new one.

# Define a common test base for starting servers
class MyBaseTestCase(unittest.TestCase):
    @classmethod
    def setUpClass(cls):
        """On inherited classes, run our `setUp` method"""
        # Inspired via http://stackoverflow.com/questions/1323455/python-unit-test-with-base-and-sub-class/17696807#17696807
        if cls is not MyBaseTestCase and cls.setUp is not MyBaseTestCase.setUp:
            orig_setUp = cls.setUp
            def setUpOverride(self, *args, **kwargs):
                MyBaseTestCase.setUp(self)
                return orig_setUp(self, *args, **kwargs)
            cls.setUp = setUpOverride

    def setUp(self):
        """Do some custom setup"""
        self.abc = True


class ItemCreateTest(MyBaseTestCase):
    def setUp(self):
        """Do more custom setup"""
        self.def = True

    def test_verify_both_setups_run(self):
        """Test for our current usage"""
        self.assertEqual(self.abc, True)
        self.assertEqual(self.def, True)
    

But if you have multiple child classes that someone else wrote and you want to add functionality in the setup and teardown, then the given code is much better than using super.

thanks man, very cool

Thanks for adding this! Also the call out for super() makes sense too. I still like this implementation.

thanks man!