    @Test
    public void immediatelyReturnsFirstPage() throws Exception {

        PokeService service = mock(PokeService.class);
        when(service.firstPokemonPage()).thenReturn(Single.just(Page.create(0, null, null, Arrays.asList(
                PokemonItem.create("bulbasaur", HttpUrl.parse("http://url"))
        ))));
        PokedexPager pager = new PokedexPager(service);
        TestSubscriber<List<PokemonItem>> subscriber = TestSubscriber.create();
        pager.pokemon().subscribe(subscriber);

        subscriber.assertReceivedOnNext(Arrays.asList(
                Arrays.asList(PokemonItem.create("bulbasaur", HttpUrl.parse("http://url")))
        ));
        subscriber.assertCompleted();
    }