def test_invalidDescriptor(self):
        """
        An implementation of L{IReactorSocket.adoptStreamPort} raises
        L{socket.error} if passed an integer which is not associated with a
        socket.
        """
        reactor = self.buildReactor()

        probe = socket.socket()
        fileno = probe.fileno()
        probe.close()

        exc = self.assertRaises(
            socket.error,
            reactor.adoptStreamPort, fileno, socket.AF_INET, ServerFactory())
        if platform.isWindows() and _PY3:
            self.assertEqual(exc.args[0], errno.WSAENOTSOCK)
        else:
            self.assertEqual(exc.args[0], errno.EBADF)

        An implementation of L{IReactorSocket.adoptStreamPort} raises
        L{socket.error} if passed an integer which is not associated with a
        socket.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_socket.py