fix: use track SID instead of source ID

pkg/rtc/mediatrack.go

@@ -241,7 +241,7 @@ func (t *MediaTrack) AddReceiver(receiver *webrtc.RTPReceiver, track *webrtc.Tra
 	defer t.lock.Unlock()
 	if t.receiver == nil {
 		// pack ID to identify all publishedTracks
-		packedId := PackTrackId(t.participantId, track.ID())
+		packedId := PackTrackId(t.participantId, t.ID())
 		t.receiver = NewWrappedReceiver(sfu.NewWebRTCReceiver(receiver, track, t.participantId), packedId)
 		t.receiver.SetRTCPCh(t.rtcpCh)
 		t.receiver.OnCloseHandler(func() {

test/singlenode_test.go

@@ -1,6 +1,7 @@
 package test
 
 import (
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -57,7 +58,7 @@ func TestSinglePublisher(t *testing.T) {
 	// a new client joins and should get the initial stream
 	c3 := createRTCClient("c3", defaultServerPort)
 
-	withTimeout(t, "c2 should receive two tracks", func() bool {
+	success := withTimeout(t, "c2 should receive two tracks", func() bool {
 		if len(c2.SubscribedTracks()) == 0 {
 			return false
 		}
@@ -70,10 +71,13 @@ func TestSinglePublisher(t *testing.T) {
 		assert.Equal(t, "webcam", tr1.StreamID())
 		return true
 	})
+	if !success {
+		t.FailNow()
+	}
 
 	// ensure that new client that has joined also received tracks
 	waitUntilConnected(t, c3)
-	withTimeout(t, "c2 should receive two tracks", func() bool {
+	success = withTimeout(t, "c2 should receive two tracks", func() bool {
 		if len(c3.SubscribedTracks()) == 0 {
 			return false
 		}
@@ -83,4 +87,13 @@ func TestSinglePublisher(t *testing.T) {
 		}
 		return true
 	})
+	if !success {
+		t.FailNow()
+	}
+
+	// ensure that the track ids are generated by server
+	tracks := c3.SubscribedTracks()[c1.ID()]
+	for _, tr := range tracks {
+		assert.True(t, strings.Contains(tr.ID(), "|TR_"), "track should begin with TR")
+	}
 }