fix subrepo break change

modules/crypto/ssh/session_test.go

@@ -0,0 +1,774 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ssh
+
+// Session tests.
+
+import (
+	"bytes"
+	crypto_rand "crypto/rand"
+	"errors"
+	"io"
+	"io/ioutil"
+	"math/rand"
+	"net"
+	"testing"
+
+	"github.com/gogits/gogs/modules/ssh/terminal"
+)
+
+type serverType func(Channel, <-chan *Request, *testing.T)
+
+// dial constructs a new test server and returns a *ClientConn.
+func dial(handler serverType, t *testing.T) *Client {
+	c1, c2, err := netPipe()
+	if err != nil {
+		t.Fatalf("netPipe: %v", err)
+	}
+
+	go func() {
+		defer c1.Close()
+		conf := ServerConfig{
+			NoClientAuth: true,
+		}
+		conf.AddHostKey(testSigners["rsa"])
+
+		_, chans, reqs, err := NewServerConn(c1, &conf)
+		if err != nil {
+			t.Fatalf("Unable to handshake: %v", err)
+		}
+		go DiscardRequests(reqs)
+
+		for newCh := range chans {
+			if newCh.ChannelType() != "session" {
+				newCh.Reject(UnknownChannelType, "unknown channel type")
+				continue
+			}
+
+			ch, inReqs, err := newCh.Accept()
+			if err != nil {
+				t.Errorf("Accept: %v", err)
+				continue
+			}
+			go func() {
+				handler(ch, inReqs, t)
+			}()
+		}
+	}()
+
+	config := &ClientConfig{
+		User: "testuser",
+	}
+
+	conn, chans, reqs, err := NewClientConn(c2, "", config)
+	if err != nil {
+		t.Fatalf("unable to dial remote side: %v", err)
+	}
+
+	return NewClient(conn, chans, reqs)
+}
+
+// Test a simple string is returned to session.Stdout.
+func TestSessionShell(t *testing.T) {
+	conn := dial(shellHandler, t)
+	defer conn.Close()
+	session, err := conn.NewSession()
+	if err != nil {
+		t.Fatalf("Unable to request new session: %v", err)
+	}
+	defer session.Close()
+	stdout := new(bytes.Buffer)
+	session.Stdout = stdout
+	if err := session.Shell(); err != nil {
+		t.Fatalf("Unable to execute command: %s", err)
+	}
+	if err := session.Wait(); err != nil {
+		t.Fatalf("Remote command did not exit cleanly: %v", err)
+	}
+	actual := stdout.String()
+	if actual != "golang" {
+		t.Fatalf("Remote shell did not return expected string: expected=golang, actual=%s", actual)
+	}
+}
+
+// TODO(dfc) add support for Std{in,err}Pipe when the Server supports it.
+
+// Test a simple string is returned via StdoutPipe.
+func TestSessionStdoutPipe(t *testing.T) {
+	conn := dial(shellHandler, t)
+	defer conn.Close()
+	session, err := conn.NewSession()
+	if err != nil {
+		t.Fatalf("Unable to request new session: %v", err)
+	}
+	defer session.Close()
+	stdout, err := session.StdoutPipe()
+	if err != nil {
+		t.Fatalf("Unable to request StdoutPipe(): %v", err)
+	}
+	var buf bytes.Buffer
+	if err := session.Shell(); err != nil {
+		t.Fatalf("Unable to execute command: %v", err)
+	}
+	done := make(chan bool, 1)
+	go func() {
+		if _, err := io.Copy(&buf, stdout); err != nil {
+			t.Errorf("Copy of stdout failed: %v", err)
+		}
+		done <- true
+	}()
+	if err := session.Wait(); err != nil {
+		t.Fatalf("Remote command did not exit cleanly: %v", err)
+	}
+	<-done
+	actual := buf.String()
+	if actual != "golang" {
+		t.Fatalf("Remote shell did not return expected string: expected=golang, actual=%s", actual)
+	}
+}
+
+// Test that a simple string is returned via the Output helper,
+// and that stderr is discarded.
+func TestSessionOutput(t *testing.T) {
+	conn := dial(fixedOutputHandler, t)
+	defer conn.Close()
+	session, err := conn.NewSession()
+	if err != nil {
+		t.Fatalf("Unable to request new session: %v", err)
+	}
+	defer session.Close()
+
+	buf, err := session.Output("") // cmd is ignored by fixedOutputHandler
+	if err != nil {
+		t.Error("Remote command did not exit cleanly:", err)
+	}
+	w := "this-is-stdout."
+	g := string(buf)
+	if g != w {
+		t.Error("Remote command did not return expected string:")
+		t.Logf("want %q", w)
+		t.Logf("got  %q", g)
+	}
+}
+
+// Test that both stdout and stderr are returned
+// via the CombinedOutput helper.
+func TestSessionCombinedOutput(t *testing.T) {
+	conn := dial(fixedOutputHandler, t)
+	defer conn.Close()
+	session, err := conn.NewSession()
+	if err != nil {
+		t.Fatalf("Unable to request new session: %v", err)
+	}
+	defer session.Close()
+
+	buf, err := session.CombinedOutput("") // cmd is ignored by fixedOutputHandler
+	if err != nil {
+		t.Error("Remote command did not exit cleanly:", err)
+	}
+	const stdout = "this-is-stdout."
+	const stderr = "this-is-stderr."
+	g := string(buf)
+	if g != stdout+stderr && g != stderr+stdout {
+		t.Error("Remote command did not return expected string:")
+		t.Logf("want %q, or %q", stdout+stderr, stderr+stdout)
+		t.Logf("got  %q", g)
+	}
+}
+
+// Test non-0 exit status is returned correctly.
+func TestExitStatusNonZero(t *testing.T) {
+	conn := dial(exitStatusNonZeroHandler, t)
+	defer conn.Close()
+	session, err := conn.NewSession()
+	if err != nil {
+		t.Fatalf("Unable to request new session: %v", err)
+	}
+	defer session.Close()
+	if err := session.Shell(); err != nil {
+		t.Fatalf("Unable to execute command: %v", err)
+	}
+	err = session.Wait()
+	if err == nil {
+		t.Fatalf("expected command to fail but it didn't")
+	}
+	e, ok := err.(*ExitError)
+	if !ok {
+		t.Fatalf("expected *ExitError but got %T", err)
+	}
+	if e.ExitStatus() != 15 {
+		t.Fatalf("expected command to exit with 15 but got %v", e.ExitStatus())
+	}
+}
+
+// Test 0 exit status is returned correctly.
+func TestExitStatusZero(t *testing.T) {
+	conn := dial(exitStatusZeroHandler, t)
+	defer conn.Close()
+	session, err := conn.NewSession()
+	if err != nil {
+		t.Fatalf("Unable to request new session: %v", err)
+	}
+	defer session.Close()
+
+	if err := session.Shell(); err != nil {
+		t.Fatalf("Unable to execute command: %v", err)
+	}
+	err = session.Wait()
+	if err != nil {
+		t.Fatalf("expected nil but got %v", err)
+	}
+}
+
+// Test exit signal and status are both returned correctly.
+func TestExitSignalAndStatus(t *testing.T) {
+	conn := dial(exitSignalAndStatusHandler, t)
+	defer conn.Close()
+	session, err := conn.NewSession()
+	if err != nil {
+		t.Fatalf("Unable to request new session: %v", err)
+	}
+	defer session.Close()
+	if err := session.Shell(); err != nil {
+		t.Fatalf("Unable to execute command: %v", err)
+	}
+	err = session.Wait()
+	if err == nil {
+		t.Fatalf("expected command to fail but it didn't")
+	}
+	e, ok := err.(*ExitError)
+	if !ok {
+		t.Fatalf("expected *ExitError but got %T", err)
+	}
+	if e.Signal() != "TERM" || e.ExitStatus() != 15 {
+		t.Fatalf("expected command to exit with signal TERM and status 15 but got signal %s and status %v", e.Signal(), e.ExitStatus())
+	}
+}
+
+// Test exit signal and status are both returned correctly.
+func TestKnownExitSignalOnly(t *testing.T) {
+	conn := dial(exitSignalHandler, t)
+	defer conn.Close()
+	session, err := conn.NewSession()
+	if err != nil {
+		t.Fatalf("Unable to request new session: %v", err)
+	}
+	defer session.Close()
+	if err := session.Shell(); err != nil {
+		t.Fatalf("Unable to execute command: %v", err)
+	}
+	err = session.Wait()
+	if err == nil {
+		t.Fatalf("expected command to fail but it didn't")
+	}
+	e, ok := err.(*ExitError)
+	if !ok {
+		t.Fatalf("expected *ExitError but got %T", err)
+	}
+	if e.Signal() != "TERM" || e.ExitStatus() != 143 {
+		t.Fatalf("expected command to exit with signal TERM and status 143 but got signal %s and status %v", e.Signal(), e.ExitStatus())
+	}
+}
+
+// Test exit signal and status are both returned correctly.
+func TestUnknownExitSignal(t *testing.T) {
+	conn := dial(exitSignalUnknownHandler, t)
+	defer conn.Close()
+	session, err := conn.NewSession()
+	if err != nil {
+		t.Fatalf("Unable to request new session: %v", err)
+	}
+	defer session.Close()
+	if err := session.Shell(); err != nil {
+		t.Fatalf("Unable to execute command: %v", err)
+	}
+	err = session.Wait()
+	if err == nil {
+		t.Fatalf("expected command to fail but it didn't")
+	}
+	e, ok := err.(*ExitError)
+	if !ok {
+		t.Fatalf("expected *ExitError but got %T", err)
+	}
+	if e.Signal() != "SYS" || e.ExitStatus() != 128 {
+		t.Fatalf("expected command to exit with signal SYS and status 128 but got signal %s and status %v", e.Signal(), e.ExitStatus())
+	}
+}
+
+// Test WaitMsg is not returned if the channel closes abruptly.
+func TestExitWithoutStatusOrSignal(t *testing.T) {
+	conn := dial(exitWithoutSignalOrStatus, t)
+	defer conn.Close()
+	session, err := conn.NewSession()
+	if err != nil {
+		t.Fatalf("Unable to request new session: %v", err)
+	}
+	defer session.Close()
+	if err := session.Shell(); err != nil {
+		t.Fatalf("Unable to execute command: %v", err)
+	}
+	err = session.Wait()
+	if err == nil {
+		t.Fatalf("expected command to fail but it didn't")
+	}
+	_, ok := err.(*ExitError)
+	if ok {
+		// you can't actually test for errors.errorString
+		// because it's not exported.
+		t.Fatalf("expected *errorString but got %T", err)
+	}
+}
+
+// windowTestBytes is the number of bytes that we'll send to the SSH server.
+const windowTestBytes = 16000 * 200
+
+// TestServerWindow writes random data to the server. The server is expected to echo
+// the same data back, which is compared against the original.
+func TestServerWindow(t *testing.T) {
+	origBuf := bytes.NewBuffer(make([]byte, 0, windowTestBytes))
+	io.CopyN(origBuf, crypto_rand.Reader, windowTestBytes)
+	origBytes := origBuf.Bytes()
+
+	conn := dial(echoHandler, t)
+	defer conn.Close()
+	session, err := conn.NewSession()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer session.Close()
+	result := make(chan []byte)
+
+	go func() {
+		defer close(result)
+		echoedBuf := bytes.NewBuffer(make([]byte, 0, windowTestBytes))
+		serverStdout, err := session.StdoutPipe()
+		if err != nil {
+			t.Errorf("StdoutPipe failed: %v", err)
+			return
+		}
+		n, err := copyNRandomly("stdout", echoedBuf, serverStdout, windowTestBytes)
+		if err != nil && err != io.EOF {
+			t.Errorf("Read only %d bytes from server, expected %d: %v", n, windowTestBytes, err)
+		}
+		result <- echoedBuf.Bytes()
+	}()
+
+	serverStdin, err := session.StdinPipe()
+	if err != nil {
+		t.Fatalf("StdinPipe failed: %v", err)
+	}
+	written, err := copyNRandomly("stdin", serverStdin, origBuf, windowTestBytes)
+	if err != nil {
+		t.Fatalf("failed to copy origBuf to serverStdin: %v", err)
+	}
+	if written != windowTestBytes {
+		t.Fatalf("Wrote only %d of %d bytes to server", written, windowTestBytes)
+	}
+
+	echoedBytes := <-result
+
+	if !bytes.Equal(origBytes, echoedBytes) {
+		t.Fatalf("Echoed buffer differed from original, orig %d, echoed %d", len(origBytes), len(echoedBytes))
+	}
+}
+
+// Verify the client can handle a keepalive packet from the server.
+func TestClientHandlesKeepalives(t *testing.T) {
+	conn := dial(channelKeepaliveSender, t)
+	defer conn.Close()
+	session, err := conn.NewSession()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer session.Close()
+	if err := session.Shell(); err != nil {
+		t.Fatalf("Unable to execute command: %v", err)
+	}
+	err = session.Wait()
+	if err != nil {
+		t.Fatalf("expected nil but got: %v", err)
+	}
+}
+
+type exitStatusMsg struct {
+	Status uint32
+}
+
+type exitSignalMsg struct {
+	Signal     string
+	CoreDumped bool
+	Errmsg     string
+	Lang       string
+}
+
+func handleTerminalRequests(in <-chan *Request) {
+	for req := range in {
+		ok := false
+		switch req.Type {
+		case "shell":
+			ok = true
+			if len(req.Payload) > 0 {
+				// We don't accept any commands, only the default shell.
+				ok = false
+			}
+		case "env":
+			ok = true
+		}
+		req.Reply(ok, nil)
+	}
+}
+
+func newServerShell(ch Channel, in <-chan *Request, prompt string) *terminal.Terminal {
+	term := terminal.NewTerminal(ch, prompt)
+	go handleTerminalRequests(in)
+	return term
+}
+
+func exitStatusZeroHandler(ch Channel, in <-chan *Request, t *testing.T) {
+	defer ch.Close()
+	// this string is returned to stdout
+	shell := newServerShell(ch, in, "> ")
+	readLine(shell, t)
+	sendStatus(0, ch, t)
+}
+
+func exitStatusNonZeroHandler(ch Channel, in <-chan *Request, t *testing.T) {
+	defer ch.Close()
+	shell := newServerShell(ch, in, "> ")
+	readLine(shell, t)
+	sendStatus(15, ch, t)
+}
+
+func exitSignalAndStatusHandler(ch Channel, in <-chan *Request, t *testing.T) {
+	defer ch.Close()
+	shell := newServerShell(ch, in, "> ")
+	readLine(shell, t)
+	sendStatus(15, ch, t)
+	sendSignal("TERM", ch, t)
+}
+
+func exitSignalHandler(ch Channel, in <-chan *Request, t *testing.T) {
+	defer ch.Close()
+	shell := newServerShell(ch, in, "> ")
+	readLine(shell, t)
+	sendSignal("TERM", ch, t)
+}
+
+func exitSignalUnknownHandler(ch Channel, in <-chan *Request, t *testing.T) {
+	defer ch.Close()
+	shell := newServerShell(ch, in, "> ")
+	readLine(shell, t)
+	sendSignal("SYS", ch, t)
+}
+
+func exitWithoutSignalOrStatus(ch Channel, in <-chan *Request, t *testing.T) {
+	defer ch.Close()
+	shell := newServerShell(ch, in, "> ")
+	readLine(shell, t)
+}
+
+func shellHandler(ch Channel, in <-chan *Request, t *testing.T) {
+	defer ch.Close()
+	// this string is returned to stdout
+	shell := newServerShell(ch, in, "golang")
+	readLine(shell, t)
+	sendStatus(0, ch, t)
+}
+
+// Ignores the command, writes fixed strings to stderr and stdout.
+// Strings are "this-is-stdout." and "this-is-stderr.".
+func fixedOutputHandler(ch Channel, in <-chan *Request, t *testing.T) {
+	defer ch.Close()
+	_, err := ch.Read(nil)
+
+	req, ok := <-in
+	if !ok {
+		t.Fatalf("error: expected channel request, got: %#v", err)
+		return
+	}
+
+	// ignore request, always send some text
+	req.Reply(true, nil)
+
+	_, err = io.WriteString(ch, "this-is-stdout.")
+	if err != nil {
+		t.Fatalf("error writing on server: %v", err)
+	}
+	_, err = io.WriteString(ch.Stderr(), "this-is-stderr.")
+	if err != nil {
+		t.Fatalf("error writing on server: %v", err)
+	}
+	sendStatus(0, ch, t)
+}
+
+func readLine(shell *terminal.Terminal, t *testing.T) {
+	if _, err := shell.ReadLine(); err != nil && err != io.EOF {
+		t.Errorf("unable to read line: %v", err)
+	}
+}
+
+func sendStatus(status uint32, ch Channel, t *testing.T) {
+	msg := exitStatusMsg{
+		Status: status,
+	}
+	if _, err := ch.SendRequest("exit-status", false, Marshal(&msg)); err != nil {
+		t.Errorf("unable to send status: %v", err)
+	}
+}
+
+func sendSignal(signal string, ch Channel, t *testing.T) {
+	sig := exitSignalMsg{
+		Signal:     signal,
+		CoreDumped: false,
+		Errmsg:     "Process terminated",
+		Lang:       "en-GB-oed",
+	}
+	if _, err := ch.SendRequest("exit-signal", false, Marshal(&sig)); err != nil {
+		t.Errorf("unable to send signal: %v", err)
+	}
+}
+
+func discardHandler(ch Channel, t *testing.T) {
+	defer ch.Close()
+	io.Copy(ioutil.Discard, ch)
+}
+
+func echoHandler(ch Channel, in <-chan *Request, t *testing.T) {
+	defer ch.Close()
+	if n, err := copyNRandomly("echohandler", ch, ch, windowTestBytes); err != nil {
+		t.Errorf("short write, wrote %d, expected %d: %v ", n, windowTestBytes, err)
+	}
+}
+
+// copyNRandomly copies n bytes from src to dst. It uses a variable, and random,
+// buffer size to exercise more code paths.
+func copyNRandomly(title string, dst io.Writer, src io.Reader, n int) (int, error) {
+	var (
+		buf       = make([]byte, 32*1024)
+		written   int
+		remaining = n
+	)
+	for remaining > 0 {
+		l := rand.Intn(1 << 15)
+		if remaining < l {
+			l = remaining
+		}
+		nr, er := src.Read(buf[:l])
+		nw, ew := dst.Write(buf[:nr])
+		remaining -= nw
+		written += nw
+		if ew != nil {
+			return written, ew
+		}
+		if nr != nw {
+			return written, io.ErrShortWrite
+		}
+		if er != nil && er != io.EOF {
+			return written, er
+		}
+	}
+	return written, nil
+}
+
+func channelKeepaliveSender(ch Channel, in <-chan *Request, t *testing.T) {
+	defer ch.Close()
+	shell := newServerShell(ch, in, "> ")
+	readLine(shell, t)
+	if _, err := ch.SendRequest("keepalive@openssh.com", true, nil); err != nil {
+		t.Errorf("unable to send channel keepalive request: %v", err)
+	}
+	sendStatus(0, ch, t)
+}
+
+func TestClientWriteEOF(t *testing.T) {
+	conn := dial(simpleEchoHandler, t)
+	defer conn.Close()
+
+	session, err := conn.NewSession()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer session.Close()
+	stdin, err := session.StdinPipe()
+	if err != nil {
+		t.Fatalf("StdinPipe failed: %v", err)
+	}
+	stdout, err := session.StdoutPipe()
+	if err != nil {
+		t.Fatalf("StdoutPipe failed: %v", err)
+	}
+
+	data := []byte(`0000`)
+	_, err = stdin.Write(data)
+	if err != nil {
+		t.Fatalf("Write failed: %v", err)
+	}
+	stdin.Close()
+
+	res, err := ioutil.ReadAll(stdout)
+	if err != nil {
+		t.Fatalf("Read failed: %v", err)
+	}
+
+	if !bytes.Equal(data, res) {
+		t.Fatalf("Read differed from write, wrote: %v, read: %v", data, res)
+	}
+}
+
+func simpleEchoHandler(ch Channel, in <-chan *Request, t *testing.T) {
+	defer ch.Close()
+	data, err := ioutil.ReadAll(ch)
+	if err != nil {
+		t.Errorf("handler read error: %v", err)
+	}
+	_, err = ch.Write(data)
+	if err != nil {
+		t.Errorf("handler write error: %v", err)
+	}
+}
+
+func TestSessionID(t *testing.T) {
+	c1, c2, err := netPipe()
+	if err != nil {
+		t.Fatalf("netPipe: %v", err)
+	}
+	defer c1.Close()
+	defer c2.Close()
+
+	serverID := make(chan []byte, 1)
+	clientID := make(chan []byte, 1)
+
+	serverConf := &ServerConfig{
+		NoClientAuth: true,
+	}
+	serverConf.AddHostKey(testSigners["ecdsa"])
+	clientConf := &ClientConfig{
+		User: "user",
+	}
+
+	go func() {
+		conn, chans, reqs, err := NewServerConn(c1, serverConf)
+		if err != nil {
+			t.Fatalf("server handshake: %v", err)
+		}
+		serverID <- conn.SessionID()
+		go DiscardRequests(reqs)
+		for ch := range chans {
+			ch.Reject(Prohibited, "")
+		}
+	}()
+
+	go func() {
+		conn, chans, reqs, err := NewClientConn(c2, "", clientConf)
+		if err != nil {
+			t.Fatalf("client handshake: %v", err)
+		}
+		clientID <- conn.SessionID()
+		go DiscardRequests(reqs)
+		for ch := range chans {
+			ch.Reject(Prohibited, "")
+		}
+	}()
+
+	s := <-serverID
+	c := <-clientID
+	if bytes.Compare(s, c) != 0 {
+		t.Errorf("server session ID (%x) != client session ID (%x)", s, c)
+	} else if len(s) == 0 {
+		t.Errorf("client and server SessionID were empty.")
+	}
+}
+
+type noReadConn struct {
+	readSeen bool
+	net.Conn
+}
+
+func (c *noReadConn) Close() error {
+	return nil
+}
+
+func (c *noReadConn) Read(b []byte) (int, error) {
+	c.readSeen = true
+	return 0, errors.New("noReadConn error")
+}
+
+func TestInvalidServerConfiguration(t *testing.T) {
+	c1, c2, err := netPipe()
+	if err != nil {
+		t.Fatalf("netPipe: %v", err)
+	}
+	defer c1.Close()
+	defer c2.Close()
+
+	serveConn := noReadConn{Conn: c1}
+	serverConf := &ServerConfig{}
+
+	NewServerConn(&serveConn, serverConf)
+	if serveConn.readSeen {
+		t.Fatalf("NewServerConn attempted to Read() from Conn while configuration is missing host key")
+	}
+
+	serverConf.AddHostKey(testSigners["ecdsa"])
+
+	NewServerConn(&serveConn, serverConf)
+	if serveConn.readSeen {
+		t.Fatalf("NewServerConn attempted to Read() from Conn while configuration is missing authentication method")
+	}
+}
+
+func TestHostKeyAlgorithms(t *testing.T) {
+	serverConf := &ServerConfig{
+		NoClientAuth: true,
+	}
+	serverConf.AddHostKey(testSigners["rsa"])
+	serverConf.AddHostKey(testSigners["ecdsa"])
+
+	connect := func(clientConf *ClientConfig, want string) {
+		var alg string
+		clientConf.HostKeyCallback = func(h string, a net.Addr, key PublicKey) error {
+			alg = key.Type()
+			return nil
+		}
+		c1, c2, err := netPipe()
+		if err != nil {
+			t.Fatalf("netPipe: %v", err)
+		}
+		defer c1.Close()
+		defer c2.Close()
+
+		go NewServerConn(c1, serverConf)
+		_, _, _, err = NewClientConn(c2, "", clientConf)
+		if err != nil {
+			t.Fatalf("NewClientConn: %v", err)
+		}
+		if alg != want {
+			t.Errorf("selected key algorithm %s, want %s", alg, want)
+		}
+	}
+
+	// By default, we get the preferred algorithm, which is ECDSA 256.
+
+	clientConf := &ClientConfig{}
+	connect(clientConf, KeyAlgoECDSA256)
+
+	// Client asks for RSA explicitly.
+	clientConf.HostKeyAlgorithms = []string{KeyAlgoRSA}
+	connect(clientConf, KeyAlgoRSA)
+
+	c1, c2, err := netPipe()
+	if err != nil {
+		t.Fatalf("netPipe: %v", err)
+	}
+	defer c1.Close()
+	defer c2.Close()
+
+	go NewServerConn(c1, serverConf)
+	clientConf.HostKeyAlgorithms = []string{"nonexistent-hostkey-algo"}
+	_, _, _, err = NewClientConn(c2, "", clientConf)
+	if err == nil {
+		t.Fatal("succeeded connecting with unknown hostkey algorithm")
+	}
+}