code: /*
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.rxjava3.internal.operators.observable;
  
  import static org.mockito.ArgumentMatchers.any;
  import static org.mockito.Mockito.*;
  
  import java.util.concurrent.TimeUnit;
  
  import io.reactivex.rxjava3.functions.Action;
  import org.junit.*;
  import org.mockito.InOrder;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.disposables.Disposable;
  import io.reactivex.rxjava3.exceptions.TestException;
  import io.reactivex.rxjava3.schedulers.TestScheduler;
  import io.reactivex.rxjava3.subjects.PublishSubject;
  import io.reactivex.rxjava3.testsupport.TestHelper;
  
  public class ObservableThrottleFirstTest extends RxJavaTest {
  
      private TestScheduler scheduler;
      private Scheduler.Worker innerScheduler;
      private Observer<String> observer;
  
      @Before
      public void before() {
          scheduler = new TestScheduler();
          innerScheduler = scheduler.createWorker();
          observer = TestHelper.mockObserver();
      }
  
      @Test
      public void throttlingWithDropCallbackCrashes() throws Throwable {
          Observable<String> source = Observable.unsafeCreate(new ObservableSource<String>() {
              @Override
              public void subscribe(Observer<? super String> innerObserver) {
                  innerObserver.onSubscribe(Disposable.empty());
                  publishNext(innerObserver, 100, "one");    // publish as it's first
                  publishNext(innerObserver, 300, "two");    // skip as it's last within the first 400
                  publishNext(innerObserver, 900, "three");   // publish
                  publishNext(innerObserver, 905, "four");   // skip
                  publishCompleted(innerObserver, 1000);     // Should be published as soon as the timeout expires.
              }
          });
  
          Action whenDisposed = mock(Action.class);
          Observable<String> sampled = source
                  .doOnDispose(whenDisposed)
                  .throttleFirst(400, TimeUnit.MILLISECONDS, scheduler, e -> {
                      if ("two".equals(e)) {
                          throw new TestException("forced");
                      }
                  });
          sampled.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
  
          scheduler.advanceTimeTo(1000, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, times(1)).onNext("one");
          inOrder.verify(observer, times(1)).onError(any(TestException.class));
          inOrder.verify(observer, times(0)).onNext("two");
          inOrder.verify(observer, times(0)).onNext("three");
          inOrder.verify(observer, times(0)).onNext("four");
          inOrder.verify(observer, times(0)).onComplete();
          inOrder.verifyNoMoreInteractions();
          verify(whenDisposed).run();
      }
  
      @Test
      public void throttlingWithDropCallback() {
          Observable<String> source = Observable.unsafeCreate(new ObservableSource<String>() {
              @Override
              public void subscribe(Observer<? super String> innerObserver) {
                  innerObserver.onSubscribe(Disposable.empty());
                  publishNext(innerObserver, 100, "one");    // publish as it's first
                  publishNext(innerObserver, 300, "two");    // skip as it's last within the first 400
                  publishNext(innerObserver, 900, "three");   // publish
                  publishNext(innerObserver, 905, "four");   // skip
                  publishCompleted(innerObserver, 1000);     // Should be published as soon as the timeout expires.
              }
          });
  
          Observer<Object> dropCallbackObserver = TestHelper.mockObserver();
          Observable<String> sampled = source.throttleFirst(400, TimeUnit.MILLISECONDS, scheduler, dropCallbackObserver::onNext);
          sampled.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
          InOrder dropCallbackOrder = inOrder(dropCallbackObserver);
  
          scheduler.advanceTimeTo(1000, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, times(1)).onNext("one");
          inOrder.verify(observer, times(0)).onNext("two");
          dropCallbackOrder.verify(dropCallbackObserver, times(1)).onNext("two");
          inOrder.verify(observer, times(1)).onNext("three");
          inOrder.verify(observer, times(0)).onNext("four");
          dropCallbackOrder.verify(dropCallbackObserver, times(1)).onNext("four");
          inOrder.verify(observer, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
          dropCallbackOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void throttlingWithCompleted() {
          Observable<String> source = Observable.unsafeCreate(new ObservableSource<String>() {
              @Override
              public void subscribe(Observer<? super String> innerObserver) {
                  innerObserver.onSubscribe(Disposable.empty());
                  publishNext(innerObserver, 100, "one");    // publish as it's first
                  publishNext(innerObserver, 300, "two");    // skip as it's last within the first 400
                  publishNext(innerObserver, 900, "three");   // publish
                  publishNext(innerObserver, 905, "four");   // skip
                  publishCompleted(innerObserver, 1000);     // Should be published as soon as the timeout expires.
              }
          });
  
          Observable<String> sampled = source.throttleFirst(400, TimeUnit.MILLISECONDS, scheduler);
          sampled.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
  
          scheduler.advanceTimeTo(1000, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, times(1)).onNext("one");
          inOrder.verify(observer, times(0)).onNext("two");
          inOrder.verify(observer, times(1)).onNext("three");
          inOrder.verify(observer, times(0)).onNext("four");
          inOrder.verify(observer, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void throttlingWithError() {
          Observable<String> source = Observable.unsafeCreate(new ObservableSource<String>() {
              @Override
              public void subscribe(Observer<? super String> innerObserver) {
                  innerObserver.onSubscribe(Disposable.empty());
                  Exception error = new TestException();
                  publishNext(innerObserver, 100, "one");    // Should be published since it is first
                  publishNext(innerObserver, 200, "two");    // Should be skipped since onError will arrive before the timeout expires
                  publishError(innerObserver, 300, error);   // Should be published as soon as the timeout expires.
              }
          });
  
          Observable<String> sampled = source.throttleFirst(400, TimeUnit.MILLISECONDS, scheduler);
          sampled.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
  
          scheduler.advanceTimeTo(400, TimeUnit.MILLISECONDS);
          inOrder.verify(observer).onNext("one");
          inOrder.verify(observer).onError(any(TestException.class));
          inOrder.verifyNoMoreInteractions();
      }
  
      private <T> void publishCompleted(final Observer<T> innerObserver, long delay) {
          innerScheduler.schedule(new Runnable() {
              @Override
              public void run() {
                  innerObserver.onComplete();
              }
          }, delay, TimeUnit.MILLISECONDS);
      }
  
      private <T> void publishError(final Observer<T> innerObserver, long delay, final Exception error) {
          innerScheduler.schedule(new Runnable() {
              @Override
              public void run() {
                  innerObserver.onError(error);
              }
          }, delay, TimeUnit.MILLISECONDS);
      }
  
      private <T> void publishNext(final Observer<T> innerObserver, long delay, final T value) {
          innerScheduler.schedule(new Runnable() {
              @Override
              public void run() {
                  innerObserver.onNext(value);
              }
          }, delay, TimeUnit.MILLISECONDS);
      }
  
      @Test
      public void throttle() {
          Observer<Integer> observer = TestHelper.mockObserver();
          TestScheduler s = new TestScheduler();
          PublishSubject<Integer> o = PublishSubject.create();
          o.throttleFirst(500, TimeUnit.MILLISECONDS, s).subscribe(observer);
  
          // send events with simulated time increments
          s.advanceTimeTo(0, TimeUnit.MILLISECONDS);
          o.onNext(1); // deliver
          o.onNext(2); // skip
          s.advanceTimeTo(501, TimeUnit.MILLISECONDS);
          o.onNext(3); // deliver
          s.advanceTimeTo(600, TimeUnit.MILLISECONDS);
          o.onNext(4); // skip
          s.advanceTimeTo(700, TimeUnit.MILLISECONDS);
          o.onNext(5); // skip
          o.onNext(6); // skip
          s.advanceTimeTo(1001, TimeUnit.MILLISECONDS);
          o.onNext(7); // deliver
          s.advanceTimeTo(1501, TimeUnit.MILLISECONDS);
          o.onComplete();
  
          InOrder inOrder = inOrder(observer);
          inOrder.verify(observer).onNext(1);
          inOrder.verify(observer).onNext(3);
          inOrder.verify(observer).onNext(7);
          inOrder.verify(observer).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void throttleFirstDefaultScheduler() {
          Observable.just(1).throttleFirst(100, TimeUnit.MILLISECONDS)
          .test()
          .awaitDone(5, TimeUnit.SECONDS)
          .assertResult(1);
      }
  
      @Test
      public void dispose() {
          TestHelper.checkDisposed(Observable.just(1).throttleFirst(1, TimeUnit.DAYS));
      }
  
      @Test
      public void doubleOnSubscribe() {
          TestHelper.checkDoubleOnSubscribeObservable(o -> o.throttleFirst(1, TimeUnit.SECONDS));
      }
  }
  