@Test
  public void testTakeWithErrorInObserver() {
    final AtomicInteger count = new AtomicInteger();
    final AtomicReference<Throwable> error = new AtomicReference<>();
    Observable.just("1", "2", "three", "4")
        .take(3)
        .safeSubscribe(
            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) {
                int num = Integer.parseInt(v);
                System.out.println(num);
                // doSomething(num);
                count.incrementAndGet();
              }
            });
    assertEquals(2, count.get());
    assertNotNull(error.get());
    if (!(error.get() instanceof NumberFormatException)) {
      fail("It should be a NumberFormatException");
    }
  }
  @Test
  public void testPublishLast() throws InterruptedException {
    final AtomicInteger count = new AtomicInteger();
    ConnectableObservable<String> connectable =
        Observable.<String>create(
                observer -> {
                  observer.onSubscribe(EmptySubscription.INSTANCE);
                  count.incrementAndGet();
                  new Thread(
                          () -> {
                            observer.onNext("first");
                            observer.onNext("last");
                            observer.onComplete();
                          })
                      .start();
                })
            .takeLast(1)
            .publish();

    // subscribe once
    final CountDownLatch latch = new CountDownLatch(1);
    connectable.subscribe(
        value -> {
          assertEquals("last", value);
          latch.countDown();
        });

    // subscribe twice
    connectable.subscribe();

    Disposable subscription = connectable.connect();
    assertTrue(latch.await(1000, TimeUnit.MILLISECONDS));
    assertEquals(1, count.get());
    subscription.dispose();
  }
  /**
   * 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 testTakeWhileToList() {
   final int expectedCount = 3;
   final AtomicInteger count = new AtomicInteger();
   for (int i = 0; i < expectedCount; i++) {
     Observable.just(Boolean.TRUE, Boolean.FALSE)
         .takeWhile(v -> v)
         .toList()
         .doOnNext(booleans -> count.incrementAndGet())
         .subscribe();
   }
   assertEquals(expectedCount, count.get());
 }
  @Test
  public void testReplay() throws InterruptedException {
    final AtomicInteger counter = new AtomicInteger();
    ConnectableObservable<String> o =
        Observable.<String>create(
                observer -> {
                  observer.onSubscribe(EmptySubscription.INSTANCE);
                  new Thread(
                          new Runnable() {

                            @Override
                            public void run() {
                              counter.incrementAndGet();
                              observer.onNext("one");
                              observer.onComplete();
                            }
                          })
                      .start();
                })
            .replay();

    // we connect immediately and it will emit the value
    Disposable s = o.connect();
    try {

      // we then expect the following 2 subscriptions to get that same value
      final CountDownLatch latch = new CountDownLatch(2);

      // subscribe once
      o.subscribe(
          v -> {
            assertEquals("one", v);
            latch.countDown();
          });

      // subscribe again
      o.subscribe(
          v -> {
            assertEquals("one", v);
            latch.countDown();
          });

      if (!latch.await(1000, TimeUnit.MILLISECONDS)) {
        fail("subscriptions did not receive values");
      }
      assertEquals(1, counter.get());
    } finally {
      s.dispose();
    }
  }
  /**
   * The error from the user provided Observer is not handled by the subscribe method try/catch.
   *
   * <p>It is handled by the AtomicObserver that wraps the provided Observer.
   *
   * <p>Result: Passes (if AtomicObserver functionality exists)
   */
  @Test
  public void testCustomObservableWithErrorInObserverAsynchronous() throws InterruptedException {
    final CountDownLatch latch = new CountDownLatch(1);
    final AtomicInteger count = new AtomicInteger();
    final AtomicReference<Throwable> error = new AtomicReference<>();

    // FIXME custom built???
    Observable.just("1", "2", "three", "4")
        .subscribeOn(Schedulers.newThread())
        .safeSubscribe(
            new Observer<String>() {
              @Override
              public void onComplete() {
                System.out.println("completed");
                latch.countDown();
              }

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

              @Override
              public void onNext(String v) {
                int num = Integer.parseInt(v);
                System.out.println(num);
                // doSomething(num);
                count.incrementAndGet();
              }
            });

    // wait for async sequence to complete
    latch.await();

    assertEquals(2, count.get());
    assertNotNull(error.get());
    if (!(error.get() instanceof NumberFormatException)) {
      fail("It should be a NumberFormatException");
    }
  }
  @Test
  public void testCacheWithCapacity() throws InterruptedException {
    final AtomicInteger counter = new AtomicInteger();
    Observable<String> o =
        Observable.<String>create(
                observer -> {
                  observer.onSubscribe(EmptySubscription.INSTANCE);
                  new Thread(
                          () -> {
                            counter.incrementAndGet();
                            observer.onNext("one");
                            observer.onComplete();
                          })
                      .start();
                })
            .cache(1);

    // we then expect the following 2 subscriptions to get that same value
    final CountDownLatch latch = new CountDownLatch(2);

    // subscribe once
    o.subscribe(
        v -> {
          assertEquals("one", v);
          latch.countDown();
        });

    // subscribe again
    o.subscribe(
        v -> {
          assertEquals("one", v);
          latch.countDown();
        });

    if (!latch.await(1000, TimeUnit.MILLISECONDS)) {
      fail("subscriptions did not receive values");
    }
    assertEquals(1, counter.get());
  }