Android架构示例单元测试实时数据

@Test
fun sendResultToUI() {

    val foo = MutableLiveData<Resource<User>>()
    val bar = MutableLiveData<Resource<User>>()
    `when`(userRepository.loadUser("foo")).thenReturn(foo)
    `when`(userRepository.loadUser("bar")).thenReturn(bar)
    val observer = mock<Observer<Resource<User>>>()
    userViewModel.user.observeForever(observer) //Create foo and bar, observe user live data

    userViewModel.setLogin("foo")
    verify(observer, never()).onChanged(any()) //Make sure that setting login to foo did not touch vm.user?

    /*val fooUser = TestUtil.createUser("foo")
    val fooValue = Resource.success(fooUser)
    foo.value = fooValue
    verify(observer).onChanged(fooValue)
    reset(observer)

    val barUser = TestUtil.createUser("bar")
    val barValue = Resource.success(barUser)
    bar.value = barValue
    userViewModel.setLogin("bar")
    verify(observer).onChanged(barValue)*/
}

谁能解释一下这句话: verify(observer, never()).onChanged(any()) GithubBrowser 样品?我只是不明白,打电话来 setLogin() 观察家那我们他妈的怎么能证实呢 onChanged() 当我们在前一行特别触发它的时候从来没有被调用过!?