使用***mockk***可以捕获值并将其存储在列表中，然后按顺序检查值。

//create mockk object
    val observer = mockk<Observer<AnyObject>>()

    //create slot
    val slot = slot<AnyObject>()

    //create list to store values
    val list = arrayListOf<AnyObject>()

    //start observing
    viewModel.postStateWithSuspend.observeForever(observer)

    //capture value on every call
    every { observer.onChanged(capture(slot)) } answers {

        //store captured value
        list.add(slot.captured)
    }

    viewModel.getPostWithSuspend()
    
    //assert your values here

我假设您正在使用mockk库
1.首先，您需要创建观察者对象

val observer = mockk<Observer<ViewState<YourObject>>> { every { onChanged(any()) } just Runs }

1.使用上一个观察者对象观察您的实时数据

viewModel.postStateWithSuspend.observeForever(observer)

1.调用getPostWithSuspend（）函数

viewModel.getPostWithSuspend()

1.核实一下

verifySequence {
        observer.onChanged(yourExpectedValue1)
        observer.onChanged(yourExpectedValue2)
    }

• 观察[LiveData]并捕获最新值和所有后续值，在有序列表中返回它们。

inline fun <reified T > LiveData<T>.captureValues(): List<T?> {
    val mockObserver = mockk<Observer<T>>()
    val list = mutableListOf<T?>()
    every { mockObserver.onChanged(captureNullable(list))} just runs
    this.observeForever(mockObserver)
    return list
}

我为LiveData编写了自己的RxJava风格测试观察器

class LiveDataTestObserver<T> constructor(
    private val liveData: LiveData<T>
) : Observer<T> {

    init {
        liveData.observeForever(this)
    }

    private val testValues = mutableListOf<T>()

    override fun onChanged(t: T) {
        if (t != null) testValues.add(t)
    }

    fun assertNoValues(): LiveDataTestObserver<T> {
        if (testValues.isNotEmpty()) throw AssertionError(
            "Assertion error with actual size ${testValues.size}"
        )
        return this
    }

    fun assertValueCount(count: Int): LiveDataTestObserver<T> {
        if (count < 0) throw AssertionError(
            "Assertion error! value count cannot be smaller than zero"
        )
        if (count != testValues.size) throw AssertionError(
            "Assertion error! with expected $count while actual ${testValues.size}"
        )
        return this
    }

    fun assertValue(vararg predicates: T): LiveDataTestObserver<T> {
        if (!testValues.containsAll(predicates.asList())) throw AssertionError("Assertion error!")
        return this
    }

    fun assertValue(predicate: (List<T>) -> Boolean): LiveDataTestObserver<T> {
        predicate(testValues)
        return this
    }

    fun values(predicate: (List<T>) -> Unit): LiveDataTestObserver<T> {
        predicate(testValues)
        return this
    }

    fun values(): List<T> {
        return testValues
    }

    /**
     * Removes this observer from the [LiveData] which was observing
     */
    fun dispose() {
        liveData.removeObserver(this)
    }

    /**
     * Clears data available in this observer and removes this observer from the [LiveData] which was observing
     */
    fun clear() {
        testValues.clear()
        dispose()
    }
}

fun <T> LiveData<T>.test(): LiveDataTestObserver<T> {

    val testObserver = LiveDataTestObserver(this)

    // Remove this testObserver that is added in init block of TestObserver, and clears previous data
    testObserver.clear()
    observeForever(testObserver)

    return testObserver
}

并将其用作

val testObserver = viewModel. postStateWithSuspend.test()

        // WHEN
        viewModel. getPostWithSuspend()

        // THEN
        testObserver
            .assertValue { states ->
                (
                    states[0].status == Status.LOADING &&
                        states[1].status == Status.ERROR
                    )
            }

嗨，你可以简单地解决这个问题，修改扩展名一点点.它是这样的：
要点是，您需要先增加锁存器计数，然后在锁存器倒计时到零之前不要删除观察器。
剩下的就很简单了，你只需要把你的结果存储在一个列表中。
祝你好运！

/*
 Add for multiple values in LiveData<T>
 */
@VisibleForTesting(otherwise = VisibleForTesting.NONE)
fun <T> LiveData<T>.getOrAwaitValuesTest(
    time: Long = 2,
    timeUnit: TimeUnit = TimeUnit.SECONDS,
    maxCountDown: Int = 1,
    afterObserve: () -> Unit = {}
): List<T?> {
    val data: MutableList<T?> = mutableListOf()
    val latch = CountDownLatch(maxCountDown)
    val observer = object : Observer<T> {
        override fun onChanged(o: T?) {
            data.add(o)
            latch.countDown()
            if (latch.count == 0L) {
                this@getOrAwaitValuesTest.removeObserver(this)
            }
        }
    }
    this.observeForever(observer)

    try {
        afterObserve.invoke()

        // Don't wait indefinitely if the LiveData is not set.
        if (!latch.await(time, timeUnit)) {
            throw TimeoutException("LiveData value was never set.")
        }

    } finally {
        this.removeObserver(observer)
    }

    return data.toList()
}

替代你可以使用mockito-kotlin

//mock the observer 
@Mock
private lateinit var observer: Observer<AnyObject>

@Test
fun `Your test`(){

  //start observing
  viewModel.postStateWithSuspend.observeForever(observer)

  //capture the values
  argumentCaptor<AnyObject>().apply {

  Mockito.verify(observer, Mockito.times(2)).onChanged(capture())
     //assert your values
   Truth.assertThat("Loading").isEqualTo(allValues[0]?.state) 
   Truth.assertThat("Network error occurred.").isEqualTo(allValues[1]?.error?.message)            
   Truth.assertThat(allValues[1]?.error).isInstanceOf(Exception::class.java)
   
    }
 //do not forget to remove the observer
 viewModel.postStateWithSuspend.removeObserver(observer)
}