@Test
public void dropAll() throws Exception {

    mList.setObserver(mObserver);
    mList.push(THING0);
    mList.push(THING1);
    verify(mObserver, times(2)).notifyItemInserted(0);
    assertEquals(2, mList.size());
    mList.dropAll();
    verify(mHandler).post(mRunnable.capture());
    mRunnable.getValue().run();
    assertEquals(0, mList.size());
    verify(mObserver).notifyItemRemoved(1);
    verify(mObserver).notifyItemRemoved(0);
    verifyNoMoreInteractions(mObserver);
}