Test the case where an RTCRtpTransceiver gets a remotely assigned mid and also unmute the associated source On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". pcA.addTrack(stream.getAudioTracks()[0], stream) A's transceiver is not yet associated with a media description and should have a null mid PASS pcA.getTransceivers()[0].mid is null A: local offer set (mid gets defined) midAssignedByA = pcA.getTransceivers()[0].mid FAIL midAssignedByA !== null should be true. Was false. pcB.addTrack(stream.getAudioTracks()[0], stream) B's transceiver is not yet associated with a media description and should have a null mid PASS pcB.getTransceivers()[0].mid is null FAIL Error in promise chain: TypeError: Member RTCSessionDescriptionInit.type is required and must be an instance of RTCSdpType PASS successfullyParsed is true TEST COMPLETE