def test_transportInterfaces(self):
        """
        The transport wrapper passed to the wrapped protocol's
        C{makeConnection} provides the same interfaces as are provided by the
        original transport.
        """
        class IStubTransport(Interface):
            pass

        @implementer(IStubTransport)
        class StubTransport:
            pass

        # Looking up what ProtocolWrapper implements also mutates the class.
        # It adds __implemented__ and __providedBy__ attributes to it.  These
        # prevent __getattr__ from causing the IStubTransport.providedBy call
        # below from returning True.  If, by accident, nothing else causes
        # these attributes to be added to ProtocolWrapper, the test will pass,
        # but the interface will only be provided until something does trigger
        # their addition.  So we just trigger it right now to be sure.
        implementedBy(policies.ProtocolWrapper)

        proto = protocol.Protocol()
        wrapper = policies.ProtocolWrapper(policies.WrappingFactory(None), proto)

        wrapper.makeConnection(StubTransport())
        self.assertTrue(IStubTransport.providedBy(proto.transport))

        The transport wrapper passed to the wrapped protocol's
        C{makeConnection} provides the same interfaces as are provided by the
        original transport.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_policies.py