def test_constructorDefaults(self):
        """
        Default values are set for the optional parameters in the endpoint.
        """
        self.assertIsInstance(self.ep._reactor, MemoryProcessReactor)
        self.assertEqual(self.ep._executable, b'/bin/executable')
        self.assertEqual(self.ep._args, ())
        self.assertEqual(self.ep._env, {})
        self.assertIsNone(self.ep._path)
        self.assertIsNone(self.ep._uid)
        self.assertIsNone(self.ep._gid)
        self.assertEqual(self.ep._usePTY, 0)
        self.assertIsNone(self.ep._childFDs)
        self.assertEqual(self.ep._errFlag, StandardErrorBehavior.LOG)

        Default values are set for the optional parameters in the endpoint.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_endpoints.py