/**
   * The error from the user provided Observable is handled by the subscribe try/catch because this
   * is synchronous
   *
   * <p>Result: Passes
   */
  @Test
  public void testCustomObservableWithErrorInObservableSynchronous() {
    final AtomicInteger count = new AtomicInteger();
    final AtomicReference<Throwable> error = new AtomicReference<>();
    // FIXME custom built???
    Observable.just("1", "2")
        .concatWith(Observable.error(() -> new NumberFormatException()))
        .subscribe(
            new Observer<String>() {

              @Override
              public void onComplete() {
                System.out.println("completed");
              }

              @Override
              public void onError(Throwable e) {
                error.set(e);
                System.out.println("error");
                e.printStackTrace();
              }

              @Override
              public void onNext(String v) {
                System.out.println(v);
                count.incrementAndGet();
              }
            });
    assertEquals(2, count.get());
    assertNotNull(error.get());
    if (!(error.get() instanceof NumberFormatException)) {
      fail("It should be a NumberFormatException");
    }
  }
  @Test
  public void testCountError() {
    Observable<String> o = Observable.error(() -> new RuntimeException());

    o.count().subscribe(w);
    verify(w, never()).onNext(anyInt());
    verify(w, never()).onComplete();
    verify(w, times(1)).onError(any(RuntimeException.class));
  }
 /**
  * https://github.com/ReactiveX/RxJava/issues/198
  *
  * <p>Rx Design Guidelines 5.2
  *
  * <p>"when calling the Subscribe method that only has an onNext argument, the OnError behavior
  * will be to rethrow the exception on the thread that the message comes out from the Observable.
  * The OnCompleted behavior in this case is to do nothing."
  */
 @Test
 @Ignore("Subscribers can't throw")
 public void testErrorThrownWithoutErrorHandlerSynchronous() {
   try {
     Observable.error(new RuntimeException("failure")).subscribe();
     fail("expected exception");
   } catch (Throwable e) {
     assertEquals("failure", e.getMessage());
   }
 }
  @Test
  public void testErrorThrownIssue1685() {
    Subject<Object, Object> subject = ReplaySubject.create();

    Observable.error(new RuntimeException("oops"))
        .materialize()
        .delay(1, TimeUnit.SECONDS)
        .dematerialize()
        .subscribe(subject);

    subject.subscribe();
    subject.materialize().toBlocking().first();

    System.out.println("Done");
  }
 @Test(expected = NullPointerException.class)
 public void testForEachWithNull() {
   Observable.error(new Exception("boo"))
       //
       .forEach(null);
 }