@Test
public void testEmpty() {

    new DimensionQueue(mTracker);
    verify(mTracker).addTrackingCallback(mCaptor.capture());
    TrackMe pre = new TrackMe();
    TrackMe post = mCaptor.getValue().onTrack(pre);
    assertThat(post, notNullValue());
    assertThat(pre, is(post));
}