def test_success(self):
        """
        L{SimpleResolverComplexifier} translates C{resolveHostName} into
        L{IResolutionReceiver.addressResolved}.
        """
        simple = SillyResolverSimple()
        complex = SimpleResolverComplexifier(simple)
        receiver = ResultHolder(self)
        self.assertEqual(receiver._started, False)
        complex.resolveHostName(receiver, u"example.com")
        self.assertEqual(receiver._started, True)
        self.assertEqual(receiver._ended, False)
        self.assertEqual(receiver._addresses, [])
        simple._requests[0].callback("192.168.1.1")
        self.assertEqual(receiver._addresses,
                         [IPv4Address('TCP', '192.168.1.1', 0)])
        self.assertEqual(receiver._ended, True)

        L{SimpleResolverComplexifier} translates C{resolveHostName} into
        L{IResolutionReceiver.addressResolved}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_resolver.py