@@ -90,6 +90,8 @@ func (rcv *Receiver) Run() error {

 			f.Close()

 			return err

 		}

+		f.Close()

+		defer peer.Close()

 		cmd := data.Message(p).Get("cmd")

 		job := rcv.Engine.Job(cmd[0], cmd[1:]...)

 		stdout, err := beam.SendRPipe(peer, data.Empty().Set("cmd", "log", "stdout").Bytes())

@@ -1,3 +1,74 @@

 package engine

-import ()

+import (

+	"bytes"

+	"fmt"

+	"github.com/dotcloud/docker/pkg/beam"

+	"strings"

+	"testing"

+	"time"

+)

+

+func TestHelloWorld(t *testing.T) {

+	testRemote(t,

+

+		// Sender side

+		func(eng *Engine) {

+			job := eng.Job("echo", "hello", "world")

+			out := &bytes.Buffer{}

+			job.Stdout.Add(out)

+			job.Run()

+			if job.status != StatusOK {

+				t.Fatalf("#%v", job.StatusCode())

+			}

+			if out.String() != "hello world\n" {

+				t.Fatalf("%#v", out.String())

+			}

+		},

+

+		// Receiver side

+		func(eng *Engine) {

+			eng.Register("echo", func(job *Job) Status {

+				fmt.Fprintf(job.Stdout, "%s\n", strings.Join(job.Args, " "))

+				return StatusOK

+			})

+		},

+	)

+}

+

+func testRemote(t *testing.T, senderSide, receiverSide func(*Engine)) {

+	sndConn, rcvConn, err := beam.USocketPair()

+	if err != nil {

+		t.Fatal(err)

+	}

+	defer sndConn.Close()

+	defer rcvConn.Close()

+	sender := NewSender(sndConn)

+	receiver := NewReceiver(rcvConn)

+

+	// Setup the sender side

+	eng := New()

+	sender.Install(eng)

+

+	// Setup the receiver side

+	receiverSide(receiver.Engine)

+	go receiver.Run()

+

+	timeout(t, func() {

+		senderSide(eng)

+	})

+}

+

+func timeout(t *testing.T, f func()) {

+	onTimeout := time.After(100 * time.Millisecond)

+	onDone := make(chan bool)

+	go func() {

+		f()

+		close(onDone)

+	}()

+	select {

+	case <-onTimeout:

+		t.Fatalf("timeout")

+	case <-onDone:

+	}

+}