def test_producerSSLFromStart(self):
        """
        C{registerProducer} and C{unregisterProducer} on TLS transports
        created as SSL from the get go are passed to the
        C{TLSMemoryBIOProtocol}, not the underlying transport directly.
        """
        result = []
        producer = FakeProducer()

        runProtocolsWithReactor(self, ConnectableProtocol(),
                                ProducerProtocol(producer, result),
                                SSLCreator())
        self.assertEqual(result, [producer, None])

        C{registerProducer} and C{unregisterProducer} on TLS transports
        created as SSL from the get go are passed to the
        C{TLSMemoryBIOProtocol}, not the underlying transport directly.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_newtls.py