如何测试 Kotlin 协程演员

Question

我已经实现了一个像官方kotlinx.coroutines docs 中的actor。现在我必须在我的仪器测试中测试它们，但我总是得到 ​​p>

IllegalStateException: This job has not completed yet

这是我的测试代码：

@RunWith(AndroidJUnit4::class)
@ExperimentalCoroutinesApi
class ExampleInstrumentedTest {

    @Test
    fun testIncrease() = runBlockingTest {
        val counter = Counter()
        for (i in 0..10) {
            counter.increase()
        }
    }

    @Test
    fun testException() = runBlockingTest {
        val counter = Counter()
        try {
            for (i in 0..11) {
                counter.increase()
            }
            Assert.fail()
        } catch (e: Exception) {
            // All good if the exception was thrown
        }
    }
}

这是演员：

sealed class CounterMsg
object IncCounter : CounterMsg()
class GetCounter(val response: CompletableDeferred<Int>) : CounterMsg()

class CounterActor {
    private val actor = GlobalScope.actor<CounterMsg> {
        var counter = 0
        for (msg in channel) {
            when (msg) {
                is IncCounter -> if (counter < 10) counter++ else throw RuntimeException()
                is GetCounter -> msg.response.complete(counter)
            }
        }
    }

    suspend fun send(message: CounterMsg) = actor.send(message)
}

class Counter {
    private val actor = CounterActor()
    suspend fun increase() = actor.send(IncCounter)
}

我的依赖：

implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.3.40"
implementation "org.jetbrains.kotlinx:kotlinx-coroutines-jdk8:1.3.0-M1"
androidTestImplementation "androidx.test.ext:junit:1.1.1"
androidTestImplementation "androidx.test:runner:1.2.0"
androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.3.40"
androidTestImplementation "org.jetbrains.kotlinx:kotlinx-coroutines-test:1.3.0-M1"

我已经尝试过GlobalScope.actor<CounterMsg>(Dispatchers.Unconfined)，它至少会将第一个测试变为绿色，但异常测试仍然失败。

Answer 1

显然，它正在进行一些小改动：

• 使用cancel() 而不是在actor中抛出异常
• 使用runBlocking 而不是runBlockingTest

Answer 2

我通过添加以下规则解决了：

@get: Rule
var instantExecutorRule = InstantTaskExecutorRule()