@Test
public void testMergeArray() {

    final Observable<String> o1 = Observable.create(new TestSynchronousObservable());
    final Observable<String> o2 = Observable.create(new TestSynchronousObservable());
    @SuppressWarnings("unchecked")
    Observable<String> m = Observable.create(mergeDelayError(o1, o2));
    m.subscribe(stringObserver);
    verify(stringObserver, never()).onError(any(Throwable.class));
    verify(stringObserver, times(2)).onNext("hello");
    verify(stringObserver, times(1)).onCompleted();
}