fix unit tests and some clean-up

modules/RTC/CodecSelection.js

      */
     constructor(conference, options) {
         this.conference = conference;
+        this.options = options;
 
         // VP8 cannot be disabled and it will be the default codec when no preference is set.
         this.disabledCodec = options.disabledCodec === CodecMimeType.VP8
 
         this.jvbPreferredCodec = jvbCodec && this._isCodecSupported(jvbCodec) ? jvbCodec : CodecMimeType.VP8;
         this.p2pPreferredCodec = p2pCodec && this._isCodecSupported(p2pCodec) ? p2pCodec : CodecMimeType.VP8;
-        this.enforcePreferredCodec = options.enforcePreferredCodec;
+        logger.debug(`Codec preferences for the conference are JVB: ${this.jvbPreferredCodec},
+            P2P: ${this.p2pPreferredCodec}`);
 
         // Do not prefer VP9 on Firefox because of the following bug.
         // https://bugzilla.mozilla.org/show_bug.cgi?id=1633876
     _onParticipantJoined(id) {
         const session = this.conference.jvbJingleSession;
 
-        if (session && !this.enforcePreferredCodec) {
+        if (session && !this.options.enforcePreferredCodec) {
             const peerMediaInfo = session.signalingLayer.getPeerMediaInfo(id, MediaType.VIDEO);
 
-            if (peerMediaInfo) {
-                const newCodec = peerMediaInfo.codecType;
-                const currentCodec = session.getConfiguredVideoCodec();
-
-                // Add the participant to the list of participants that
-                // don't support the preferred codec.
-                if (newCodec !== this.jvbPreferredCodec) {
-                    this.nonPreferredParticipants.push(id);
-                }
-                logger.warn(`Current: ${currentCodec}, new: ${newCodec}`);
-                if (newCodec
-                    && newCodec !== this.jvbPreferredCodec
-                    && newCodec !== currentCodec
-                    && this._isCodecSupported(newCodec)) {
-                    session.setVideoCodecs(newCodec);
-                }
+            if (!peerMediaInfo) {
+                return;
+            }
+            const newCodec = peerMediaInfo.codecType;
+            const currentCodec = session.getConfiguredVideoCodec();
+
+            if (newCodec
+                && newCodec !== this.jvbPreferredCodec
+                && newCodec !== currentCodec
+                && this._isCodecSupported(newCodec)) {
+
+                // Add the participant to the list of participants that don't support the preferred codec.
+                this.nonPreferredParticipants.push(id);
+                session.setVideoCodecs(newCodec);
             }
         }
     }
     _onParticipantLeft(id) {
         const session = this.conference.jvbJingleSession;
 
-        if (session && !this.enforcePreferredCodec) {
+        if (session && !this.options.enforcePreferredCodec) {
             const index = this.nonPreferredParticipants.findIndex(participantId => participantId === id);
 
             if (index > -1) {

modules/RTC/MockClasses.js

         return Promise.resolve(/* answer */{});
     }
 
+    /**
+     * {@link TraceablePeerConnection.getConfiguredVideoCodec}.
+     *
+     * @returns {CodecMimeType}
+     */
+    getConfiguredVideoCodec() {
+        return 'vp8';
+    }
+
     /**
      * {@link TraceablePeerConnection.setLocalDescription}.
      *

modules/xmpp/ChatRoom.js

         this.addVideoInfoToPresence(false);
 
         // Set the default codec.
-        this.addCodecInfoToPresence(this.options.preferredCodec);
+        this.addCodecInfoToPresence(options.preferredCodec);
 
         if (options.deploymentInfo && options.deploymentInfo.userRegion) {
             this.presMap.nodes.push({

modules/xmpp/ChatRoom.spec.js

                 'jid',
                 'password',
                 xmpp,
-                {} /* options */);
+                { preferredCodec: 'vp8' } /* options */);
             emitterSpy = spyOn(room.eventEmitter, 'emit');
         });
         it('parses status correctly', () => {

modules/xmpp/JingleSessionPC.js

     }
 
     /**
-     *
+     * Returns the video codec configured as the preferred codec on the peerconnection.
      */
     getConfiguredVideoCodec() {
         return this.peerconnection.getConfiguredVideoCodec();
     }
 
     /**
+     * Updates the codecs on the peerconnection and initiates a renegotiation for the
+     * new codec config to take effect.
      *
-     * @param {*} codec
+     * @param {CodecMimeType} preferred the preferred codec.
+     * @param {CodecMimeType} disabled the codec that needs to be disabled.
      */
     setVideoCodecs(preferred = null, disabled = null) {
         const current = this.peerconnection.getConfiguredVideoCodec();

modules/xmpp/MockClasses.js

      */
     addPresenceListener() {
     }
+
+    /**
+     * {@link ChatRoom.sendCodecInfoPresence}.
+     */
+    sendCodecInfoPresence() {
+    }
 }
 
 /**