@Test
public void testElementAtOrDefault() throws InterruptedException,
        ExecutionException {

    Observable<Integer> w = Observable.from(1, 2);
    Observable<Integer> observable = Observable
            .create(elementAtOrDefault(w, 1, 0));
    @SuppressWarnings("unchecked")
    Observer<Integer> observer = mock(Observer.class);
    observable.subscribe(observer);
    verify(observer, never()).onNext(1);
    verify(observer, times(1)).onNext(2);
    verify(observer, never()).onError(any(Throwable.class));
    verify(observer, times(1)).onCompleted();
}