    sourceBuffer.videoTracks[0].selected = false;
                  });

                  test.waitForExpectedEvents(function()
                  {
                      assert_equals(mediaSource.activeSourceBuffers.length, 1,
                        "activeSourceBuffers list unchanged");
                      test.done();
                  });
              });
          }, "Active SourceBuffers list ignores changes to selected audio/video tracks " +
            "that do not affect the activation of the S