ObservableToSingle_firstOrError.kt

@Test
fun `observable to single with firstOrError`() {
   val observable = Observable.fromIterable<Int>((1..5).toList())
       .doOnNext { println("Source observable emitting $it") }

   val single = observable.firstOrError()
       .doOnSuccess { println("Single succeeded with value: $it") }

   val testObserver = single.test().await()

   testObserver.apply {
        assertComplete()
        assertValue(1)
    }
}