@Test
fun `observable to single with first() and default value`() {
    val observable = Observable.fromIterable<Int>((1..5).toList())
    assertObservableToSingle(observable, { first(-1)}) {
        assertComplete()
        assertValue(1)
    }

    val emptyObservable = Observable.empty<Int>()
    assertObservableToSingle(emptyObservable, { first(-1)}) {
        assertComplete()
        assertValue(-1)
    }
}