PublishSubject和TestScheduler出现问题,未发出项目

时间:2018-11-28 12:19:22

标签: android unit-testing testing rx-java rx-android

我一直遇到主题和TestSchedulers的问题。如果我使用蹦床调度程序,则测试通过,但由于某些原因,如果使用TestScheduler,则测试失败。

这是我的示例测试和相关课程。

@RunWith(MockitoJUnitRunner::class)
class DemoViewModelTest  {


    //Error Mocks
    private val actionsStream: PublishSubject<DemoContract.ViewEvent> = PublishSubject.create()

    private lateinit var viewModel: DemoViewModel

    private val handler = mock(DemoContract.Handler::class.java)

    @Before
    fun setup() {
        viewModel = DemoViewModel(schedulersProvider, handler)
        viewModel.viewEventsStream = actionsStream
    }

    @Test
    fun testUpdateCounter() {
        actionsStream.onNext(DemoContract.ViewEvent.UpdateClick)
        testScheduler.triggerActions()
        verify(handler).onUpdate()

    }


    protected var testScheduler = TestScheduler()

    protected var schedulersProvider: SchedulersProvider = object : SchedulersProvider() {
        override fun mainThread(): Scheduler {
            return testScheduler
        }

        override fun io(): Scheduler {
            return testScheduler
        }

        override fun computation(): Scheduler {
            return testScheduler
        }

        override fun newThread(): Scheduler {
            return testScheduler
        }

        override fun trampoline(): Scheduler {
            return testScheduler
        }

        override fun single(): Scheduler {
            return testScheduler
        }
    }
}

还有我的ViewModel类

class DemoViewModel (val schedulersProvider: SchedulersProvider, val handler:DemoContract.Handler) : DemoContract.ViewModel() {

    var viewEventsStream: Observable<DemoContract.ViewEvent>? = null
        set(value) {
            field = value
            subscribeToViewEvents()
        }

    private fun subscribeToViewEvents() {
        viewEventsStream?.let {
            it.subscribeOn(schedulersProvider.io())
                .observeOn(schedulersProvider.mainThread())
                .subscribe(object:Observer<DemoContract.ViewEvent>{
                    override fun onComplete() {

                    }

                    override fun onSubscribe(d: Disposable) {
                    }

                    override fun onNext(t: DemoContract.ViewEvent) {
                        onViewEvent(t)
                    }

                    override fun onError(e: Throwable) {
                    }

                })

        }
    }
     fun onViewEvent(event: DemoContract.ViewEvent) {
        when (event) {
            is DemoContract.ViewEvent.UpdateClick -> {
               handler.onUpdate()
            }
        }
    }

}

“我的合同”类别是

interface DemoContract {
        abstract class ViewModel

        sealed class ViewEvent {
            object UpdateClick : ViewEvent()
        }

        interface Handler{
            fun onUpdate()
        }
    }

有关此事,如果我替换

viewModel.viewEventsStream = actionsStream

使用

viewModel.viewEventsStream = Observable.just(DemoContract.ViewEvent.Update)

此测试通过。

有人可以对此发表一些看法,在此先感谢。这是最小可运行的project

1 个答案:

答案 0 :(得分:2)

非常感谢@akarnokd向我指出正确的方向。事实证明,这是订户要添加的PublishSubjectsubscribeActual调用)与我在测试中触发的onNext调用之间的竞争条件。 onNext呼叫在前者发生之前返回。

解决方案是在订阅后立即一次发出一次triggerActions,并在发射后一次明确调用一次。

更改此

    @Before
    fun setup() {
        viewModel = DemoViewModel(schedulersProvider, handler)
        viewModel.viewEventsStream = actionsStream
    }

收件人

    @Before
    fun setup() {
        viewModel = DemoViewModel(schedulersProvider, handler)
        viewModel.viewEventsStream = actionsStream
        testScheduler.triggerActions()
    }