def test_passwordAuthenticationFailure(self):
        """
        If the SSH server rejects the password presented during authentication,
        the L{Deferred} returned by L{SSHCommandClientEndpoint.connect} fires
        with a L{Failure} wrapping L{AuthenticationFailed}.
        """
        endpoint = SSHCommandClientEndpoint.newConnection(
            self.reactor, b"/bin/ls -l", b"dummy user",
            self.hostname, self.port,  password=b"dummy password",
            knownHosts=self.knownHosts, ui=FixedResponseUI(False))

        factory = Factory()
        factory.protocol = Protocol
        connected = endpoint.connect(factory)

        server, client, pump = self.connectedServerAndClient(
            self.factory, self.reactor.tcpClients[0][2])

        # For security, the server delays password authentication failure
        # response.  Advance the simulation clock so the client sees the
        # failure.
        self.reactor.advance(server.service.passwordDelay)

        # Let the failure response traverse the "network"
        pump.flush()

        f = self.failureResultOf(connected)
        f.trap(AuthenticationFailed)
        # XXX Should assert something specific about the arguments of the
        # exception

        self.assertClientTransportState(client, False)

        If the SSH server rejects the password presented during authentication,
        the L{Deferred} returned by L{SSHCommandClientEndpoint.connect} fires
        with a L{Failure} wrapping L{AuthenticationFailed}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_endpoints.py