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.observable;
  
  import static org.junit.Assert.*;
  
  import java.util.concurrent.atomic.*;
  
  import org.junit.Test;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.exceptions.TestException;
  import io.reactivex.rxjava3.functions.*;
  
  public class ObservableDoOnTest extends RxJavaTest {
  
      @Test
      public void doOnEach() {
          final AtomicReference<String> r = new AtomicReference<>();
          String output = Observable.just("one").doOnNext(new Consumer<String>() {
              @Override
              public void accept(String v) {
                  r.set(v);
              }
          }).blockingSingle();
  
          assertEquals("one", output);
          assertEquals("one", r.get());
      }
  
      @Test
      public void doOnError() {
          final AtomicReference<Throwable> r = new AtomicReference<>();
          Throwable t = null;
          try {
              Observable.<String> error(new RuntimeException("an error"))
              .doOnError(new Consumer<Throwable>() {
                  @Override
                  public void accept(Throwable v) {
                      r.set(v);
                  }
              }).blockingSingle();
              fail("expected exception, not a return value");
          } catch (Throwable e) {
              t = e;
          }
  
          assertNotNull(t);
          assertEquals(t, r.get());
      }
  
      @Test
      public void doOnCompleted() {
          final AtomicBoolean r = new AtomicBoolean();
          String output = Observable.just("one").doOnComplete(new Action() {
              @Override
              public void run() {
                  r.set(true);
              }
          }).blockingSingle();
  
          assertEquals("one", output);
          assertTrue(r.get());
      }
  
      @Test
      public void doOnTerminateComplete() {
          final AtomicBoolean r = new AtomicBoolean();
          String output = Observable.just("one").doOnTerminate(new Action() {
              @Override
              public void run() {
                  r.set(true);
              }
          }).blockingSingle();
  
          assertEquals("one", output);
          assertTrue(r.get());
  
      }
  
      @Test
      public void doOnTerminateError() {
          final AtomicBoolean r = new AtomicBoolean();
          Observable.<String>error(new TestException()).doOnTerminate(new Action() {
              @Override
              public void run() {
                  r.set(true);
              }
          })
          .test()
          .assertFailure(TestException.class);
          assertTrue(r.get());
      }
  }
  