@Test
public void testCheckChangeItemSuccess() throws Exception {

    when(mRepository.createOrUpdate(any(Todo.class))).thenAnswer(invocation -> {
        Object[] args = invocation.getArguments();
        return Observable.just((Todo) args[0]);
    });
    fetchData();
    mViewModel.checkChangeItem(mItemViewModelList.get(0)).toBlocking().single();
    assertTrue(mItemViewModelList.get(0).isCompleted());
}