Add test for updateLocalUsermediaStream (#2596)

spec/test-utils/webrtc.ts

@@ -148,6 +148,7 @@ export class MockMediaStream {
     ) {}
 
     listeners: [string, (...args: any[]) => any][] = [];
+    public isStopped = false;
 
     dispatchEvent(eventType: string) {
         this.listeners.forEach(([t, c]) => {
@@ -196,7 +197,9 @@ export class MockMediaHandler {
         this.userMediaStreams.push(stream);
         return stream;
     }
-    stopUserMediaStream() { }
+    stopUserMediaStream(stream: MockMediaStream) {
+        stream.isStopped = true;
+    }
     hasAudioDevice() { return true; }
     hasVideoDevice() { return true; }
     stopAllStreams() {}

spec/unit/webrtc/groupCall.spec.ts

@@ -263,6 +263,33 @@ describe('Group Call', function() {
                 groupCall.leave();
             }
         });
+
+        it("retains state of local user media stream when updated", async () => {
+            try {
+                await groupCall.create();
+
+                await groupCall.initLocalCallFeed();
+
+                const oldStream = groupCall.localCallFeed.stream as unknown as MockMediaStream;
+
+                // arbitrary values, important part is that they're the same afterwards
+                await groupCall.setLocalVideoMuted(true);
+                await groupCall.setMicrophoneMuted(false);
+
+                const newStream = await mockClient.getMediaHandler().getUserMediaStream(true, true);
+
+                groupCall.updateLocalUsermediaStream(newStream);
+
+                expect(groupCall.localCallFeed.stream).toBe(newStream);
+
+                expect(groupCall.isLocalVideoMuted()).toEqual(true);
+                expect(groupCall.isMicrophoneMuted()).toEqual(false);
+
+                expect(oldStream.isStopped).toEqual(true);
+            } finally {
+                groupCall.leave();
+            }
+        });
     });
 
     describe('Placing calls', function() {