@Test
@SuppressWarnings("unchecked")
public void testDematerialize3() {

    Exception exception = new Exception("test");
    Observable<Integer> observable = Observable.error(exception);
    Observable<Integer> dematerialize = Observable.create(dematerialize(observable.materialize()));
    Observer<Integer> observer = mock(Observer.class);
    dematerialize.subscribe(observer);
    verify(observer, times(1)).onError(exception);
    verify(observer, times(0)).onCompleted();
    verify(observer, times(0)).onNext(any(Integer.class));
}