def test_empty(self):
        """
        A monkey patcher without patches shouldn't change a thing.
        """
        self.monkeyPatcher.patch()

        # We can't assert that all state is unchanged, but at least we can
        # check our test object.
        self.assertEqual(self.originalObject.foo, self.testObject.foo)
        self.assertEqual(self.originalObject.bar, self.testObject.bar)
        self.assertEqual(self.originalObject.baz, self.testObject.baz)

        A monkey patcher without patches shouldn't change a thing.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_monkey.py