RxJava repeatWhen example

test.kt

    @Test
    fun test_repeating_api_request() {
        val scheduler = TestScheduler()

        var apiRequestCount = 0

        val apiRequest = {
            if (apiRequestCount < 5) {
                apiRequestCount++
                Observable.just("wait")
            } else {
                Observable.just("finished")
            }
        }

        val repeating = Observable
                .defer(apiRequest)
                .repeatWhen { it.delay(5, TimeUnit.SECONDS, scheduler)  }
                .filter { it == "finished" }
                .take(1)
                .flatMap { Observable.just(it) }


        val test = repeating.test()

        test.assertNoValues()

        scheduler.advanceTimeBy(5, TimeUnit.SECONDS)
        test.assertNoValues()

        scheduler.advanceTimeBy(5, TimeUnit.SECONDS)
        test.assertNoValues()

        scheduler.advanceTimeBy(5, TimeUnit.SECONDS)
        test.assertNoValues()

        scheduler.advanceTimeBy(5, TimeUnit.SECONDS)
        test.assertNoValues()

        scheduler.advanceTimeBy(5, TimeUnit.SECONDS)
        test.assertValue { it == "finished" }
        test.assertComplete()

    }
    
     @Test
    fun test_repeating_api_error() {
        val scheduler = TestScheduler()

        var apiRequestCount = 0

        val apiRequest = {
            if (apiRequestCount < 5) {
                apiRequestCount++
                Observable.just("wait")
            } else {
                Observable.error(Exception("error"))
            }
        }

        val repeating = Observable
                .defer(apiRequest)
                .repeatWhen { it.delay(5, TimeUnit.SECONDS, scheduler)  }
                .filter { it == "finished" }
                .take(1)
                .flatMap { Observable.just(it) }


        val test = repeating.test()

        test.assertNoValues()

        scheduler.advanceTimeBy(5, TimeUnit.SECONDS)
        test.assertNoValues()

        scheduler.advanceTimeBy(5, TimeUnit.SECONDS)
        test.assertNoValues()

        scheduler.advanceTimeBy(5, TimeUnit.SECONDS)
        test.assertNoValues()

        scheduler.advanceTimeBy(5, TimeUnit.SECONDS)
        test.assertNoValues()

        scheduler.advanceTimeBy(5, TimeUnit.SECONDS)
        test.assertError { it.message == "error" }

    }