OperationFilter { public static <T> OnSubscribeFunc<T> filter(Observable<? extends T> that, Func1<? super T, Boolean> predicate) { return new Filter<T>(that, predicate); }  static OnSubscribeFunc<T> filter(Observable<? extends T> that, Func1<? super T, Boolean> predicate);  }
@Test public void testFilter() { Observable<String> w = Observable.from("one", "two", "three"); Observable<String> observable = Observable.create(filter(w, new Func1<String, Boolean>() { @Override public Boolean call(String t1) { return t1.equals("two"); } })); @SuppressWarnings("unchecked") Observer<String> observer = mock(Observer.class); observable.subscribe(observer); verify(observer, Mockito.never()).onNext("one"); verify(observer, times(1)).onNext("two"); verify(observer, Mockito.never()).onNext("three"); verify(observer, Mockito.never()).onError(any(Throwable.class)); verify(observer, times(1)).onCompleted(); }