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.junit.Assert.*;
  
  import java.util.Arrays;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import org.junit.Test;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.disposables.*;
  import io.reactivex.rxjava3.functions.Consumer;
  import io.reactivex.rxjava3.observers.DefaultObserver;
  
  public class ObservableSwitchIfEmptyTest extends RxJavaTest {
  
      @Test
      public void switchWhenNotEmpty() throws Exception {
          final AtomicBoolean subscribed = new AtomicBoolean(false);
          final Observable<Integer> o = Observable.just(4)
                  .switchIfEmpty(Observable.just(2)
                  .doOnSubscribe(new Consumer<Disposable>() {
                      @Override
                      public void accept(Disposable d) {
                          subscribed.set(true);
                      }
                  }));
  
          assertEquals(4, o.blockingSingle().intValue());
          assertFalse(subscribed.get());
      }
  
      @Test
      public void switchWhenEmpty() throws Exception {
          final Observable<Integer> o = Observable.<Integer>empty()
                  .switchIfEmpty(Observable.fromIterable(Arrays.asList(42)));
  
          assertEquals(42, o.blockingSingle().intValue());
      }
  
      @Test
      public void switchTriggerUnsubscribe() throws Exception {
  
          final Disposable d = Disposable.empty();
  
          Observable<Long> withProducer = Observable.unsafeCreate(new ObservableSource<Long>() {
              @Override
              public void subscribe(final Observer<? super Long> observer) {
                  observer.onSubscribe(d);
                  observer.onNext(42L);
              }
          });
  
          Observable.<Long>empty()
                  .switchIfEmpty(withProducer)
                  .lift(new ObservableOperator<Long, Long>() {
              @Override
              public Observer<? super Long> apply(final Observer<? super Long> child) {
                  return new DefaultObserver<Long>() {
                      @Override
                      public void onComplete() {
  
                      }
  
                      @Override
                      public void onError(Throwable e) {
  
                      }
  
                      @Override
                      public void onNext(Long aLong) {
                          cancel();
                      }
  
                  };
              }
          }).subscribe();
  
          assertTrue(d.isDisposed());
          // FIXME no longer assertable
  //        assertTrue(sub.isUnsubscribed());
      }
  
      @Test
      public void switchShouldTriggerUnsubscribe() {
          final Disposable d = Disposable.empty();
  
          Observable.unsafeCreate(new ObservableSource<Long>() {
              @Override
              public void subscribe(final Observer<? super Long> observer) {
                  observer.onSubscribe(d);
                  observer.onComplete();
              }
          }).switchIfEmpty(Observable.<Long>never()).subscribe();
          assertTrue(d.isDisposed());
      }
  }
  