             "audio track list contains loaded audio track");
                          assert_equals(sourceBufferVideo.videoTracks.length, 1,
                            "video track list contains loaded video track");

                          test.expectEvent(mediaSource.activeSourceBuffers, "removesourcebuffer");
                          sourceBufferAudio.audioTracks[0].enabled = false;
                      });

                      test.waitForExpectedEvents(function()
                      {
     