def test_wrappedProtocolHandshakeCompleted(self):
        """
        L{_WrappingProtocol.handshakeCompleted} should proxy to the
        wrapped protocol's C{handshakeCompleted}
        """
        listener = TestHandshakeListener()
        wrapped = endpoints._WrappingProtocol(None, listener)
        wrapped.handshakeCompleted()
        self.assertEqual(listener.handshakeCompletedCalls, 1)

        L{_WrappingProtocol.handshakeCompleted} should proxy to the
        wrapped protocol's C{handshakeCompleted}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_endpoints.py