add tests

ssh/tcpip.go

@@ -343,7 +343,7 @@ func (c *Client) Dial(n, addr string) (net.Conn, error) {
 		if err != nil {
 			return nil, err
 		}
-		port, err := net.LookupPort(portString)
+		port, err := net.LookupPort(n, portString)
 		if err != nil {
 			return nil, err
 		}

ssh/tcpip_test.go

@@ -5,6 +5,7 @@
 package ssh
 
 import (
+	"fmt"
 	"testing"
 )
 
@@ -18,3 +19,60 @@ func TestAutoPortListenBroken(t *testing.T) {
 		t.Errorf("version %q marked as broken", works)
 	}
 }
+
+func TestDialNamedPort(t *testing.T) {
+	// Test that sshClient.Dial supports named ports.
+
+	srvConn, clientConn, err := netPipe()
+	if err != nil {
+		t.Fatalf("netPipe: %v", err)
+	}
+
+	serverConf := &ServerConfig{
+		NoClientAuth: true,
+	}
+	serverConf.AddHostKey(testSigners["rsa"])
+	srvErr := make(chan error, 1)
+	go func() {
+		defer close(srvErr)
+		_, chans, req, err := NewServerConn(srvConn, serverConf)
+		if err != nil {
+			srvErr <- fmt.Errorf("NewServerConn: %w", err)
+			return
+		}
+		go DiscardRequests(req)
+		for newChan := range chans {
+			ch, reqs, err := newChan.Accept()
+			if err != nil {
+				srvErr <- fmt.Errorf("Accept: %w", err)
+			}
+			go DiscardRequests(reqs)
+			ch.Close()
+		}
+	}()
+
+	clientConf := &ClientConfig{
+		User:            "testuser",
+		HostKeyCallback: InsecureIgnoreHostKey(),
+	}
+
+	sshClientConn, newChans, reqs, err := NewClientConn(clientConn, "", clientConf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	sshClient := NewClient(sshClientConn, newChans, reqs)
+
+	// port being a named port `ssh` is the main point of the test.
+	tcpipconn, err := sshClient.Dial("tcp", "localhost:ssh")
+	if err != nil {
+		t.Fatal(err)
+	}
+	tcpipconn.Close()
+
+	srvConn.Close()
+	clientConn.Close()
+
+	for err := range srvErr {
+		t.Errorf("ssh server: %s", err)
+	}
+}