func (s *server) TryDial(config *ssh.ClientConfig) (*ssh.Client, error) {
	sshd, err := exec.LookPath("sshd")
	if err != nil {
		s.t.Skipf("skipping test: %v", err)
	}

	c1, c2, err := unixConnection()
	if err != nil {
		s.t.Fatalf("unixConnection: %v", err)
	}

	s.cmd = exec.Command(sshd, "-f", s.configfile, "-i", "-e")
	f, err := c2.File()
	if err != nil {
		s.t.Fatalf("UnixConn.File: %v", err)
	}
	defer f.Close()
	s.cmd.Stdin = f
	s.cmd.Stdout = f
	s.cmd.Stderr = &s.output
	if err := s.cmd.Start(); err != nil {
		s.t.Fail()
		s.Shutdown()
		s.t.Fatalf("s.cmd.Start: %v", err)
	}
	s.clientConn = c1
	conn, chans, reqs, err := ssh.NewClientConn(c1, "", config)
	if err != nil {
		return nil, err
	}
	return ssh.NewClient(conn, chans, reqs), nil
}
func TestSetupForwardAgent(t *testing.T) {
	a, b, err := netPipe()
	if err != nil {
		t.Fatalf("netPipe: %v", err)
	}

	defer a.Close()
	defer b.Close()

	_, socket, cleanup := startAgent(t)
	defer cleanup()

	serverConf := ssh.ServerConfig{
		NoClientAuth: true,
	}
	serverConf.AddHostKey(testSigners["rsa"])
	incoming := make(chan *ssh.ServerConn, 1)
	go func() {
		conn, _, _, err := ssh.NewServerConn(a, &serverConf)
		if err != nil {
			t.Fatalf("Server: %v", err)
		}
		incoming <- conn
	}()

	conf := ssh.ClientConfig{}
	conn, chans, reqs, err := ssh.NewClientConn(b, "", &conf)
	if err != nil {
		t.Fatalf("NewClientConn: %v", err)
	}
	client := ssh.NewClient(conn, chans, reqs)

	if err := ForwardToRemote(client, socket); err != nil {
		t.Fatalf("SetupForwardAgent: %v", err)
	}

	server := <-incoming
	ch, reqs, err := server.OpenChannel(channelType, nil)
	if err != nil {
		t.Fatalf("OpenChannel(%q): %v", channelType, err)
	}
	go ssh.DiscardRequests(reqs)

	agentClient := NewClient(ch)
	testAgentInterface(t, agentClient, testPrivateKeys["rsa"], nil)
	conn.Close()
}
func TestAuth(t *testing.T) {
	a, b, err := netPipe()
	if err != nil {
		t.Fatalf("netPipe: %v", err)
	}

	defer a.Close()
	defer b.Close()

	agent, _, cleanup := startAgent(t)
	defer cleanup()

	if err := agent.Add(testPrivateKeys["rsa"], nil, "comment"); err != nil {
		t.Errorf("Add: %v", err)
	}

	serverConf := ssh.ServerConfig{}
	serverConf.AddHostKey(testSigners["rsa"])
	serverConf.PublicKeyCallback = func(c ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissions, error) {
		if bytes.Equal(key.Marshal(), testPublicKeys["rsa"].Marshal()) {
			return nil, nil
		}

		return nil, errors.New("pubkey rejected")
	}

	go func() {
		conn, _, _, err := ssh.NewServerConn(a, &serverConf)
		if err != nil {
			t.Fatalf("Server: %v", err)
		}
		conn.Close()
	}()

	conf := ssh.ClientConfig{}
	conf.Auth = append(conf.Auth, ssh.PublicKeysCallback(agent.Signers))
	conn, _, _, err := ssh.NewClientConn(b, "", &conf)
	if err != nil {
		t.Fatalf("NewClientConn: %v", err)
	}
	conn.Close()
}