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.flowable;
  
  import static org.junit.Assert.*;
  import static org.mockito.ArgumentMatchers.any;
  import static org.mockito.Mockito.*;
  
  import java.io.IOException;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicReference;
  
  import org.junit.Test;
  import org.mockito.Mockito;
  import org.reactivestreams.*;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.exceptions.TestException;
  import io.reactivex.rxjava3.functions.Function;
  import io.reactivex.rxjava3.internal.functions.Functions;
  import io.reactivex.rxjava3.internal.subscriptions.BooleanSubscription;
  import io.reactivex.rxjava3.processors.PublishProcessor;
  import io.reactivex.rxjava3.schedulers.Schedulers;
  import io.reactivex.rxjava3.subscribers.TestSubscriber;
  import io.reactivex.rxjava3.testsupport.TestHelper;
  
  public class FlowableOnErrorResumeNextViaFunctionTest extends RxJavaTest {
  
      @Test
      public void resumeNextWithSynchronousExecution() {
          final AtomicReference<Throwable> receivedException = new AtomicReference<>();
          Flowable<String> w = Flowable.unsafeCreate(new Publisher<String>() {
  
              @Override
              public void subscribe(Subscriber<? super String> subscriber) {
                  subscriber.onSubscribe(new BooleanSubscription());
                  subscriber.onNext("one");
                  subscriber.onError(new Throwable("injected failure"));
                  subscriber.onNext("two");
                  subscriber.onNext("three");
              }
          });
  
          Function<Throwable, Flowable<String>> resume = new Function<Throwable, Flowable<String>>() {
  
              @Override
              public Flowable<String> apply(Throwable t1) {
                  receivedException.set(t1);
                  return Flowable.just("twoResume", "threeResume");
              }
  
          };
          Flowable<String> flowable = w.onErrorResumeNext(resume);
  
          Subscriber<String> subscriber = TestHelper.mockSubscriber();
  
          flowable.subscribe(subscriber);
  
          verify(subscriber, Mockito.never()).onError(any(Throwable.class));
          verify(subscriber, times(1)).onComplete();
          verify(subscriber, times(1)).onNext("one");
          verify(subscriber, Mockito.never()).onNext("two");
          verify(subscriber, Mockito.never()).onNext("three");
          verify(subscriber, times(1)).onNext("twoResume");
          verify(subscriber, times(1)).onNext("threeResume");
          assertNotNull(receivedException.get());
      }
  
      @Test
      public void resumeNextWithAsyncExecution() {
          final AtomicReference<Throwable> receivedException = new AtomicReference<>();
          Subscription s = mock(Subscription.class);
          TestFlowable w = new TestFlowable(s, "one");
          Function<Throwable, Flowable<String>> resume = new Function<Throwable, Flowable<String>>() {
  
              @Override
              public Flowable<String> apply(Throwable t1) {
                  receivedException.set(t1);
                  return Flowable.just("twoResume", "threeResume");
              }
  
          };
          Flowable<String> flowable = Flowable.unsafeCreate(w).onErrorResumeNext(resume);
  
          Subscriber<String> subscriber = TestHelper.mockSubscriber();
  
          flowable.subscribe(subscriber);
  
          try {
              w.t.join();
          } catch (InterruptedException e) {
              fail(e.getMessage());
          }
  
          verify(subscriber, Mockito.never()).onError(any(Throwable.class));
          verify(subscriber, times(1)).onComplete();
          verify(subscriber, times(1)).onNext("one");
          verify(subscriber, Mockito.never()).onNext("two");
          verify(subscriber, Mockito.never()).onNext("three");
          verify(subscriber, times(1)).onNext("twoResume");
          verify(subscriber, times(1)).onNext("threeResume");
          assertNotNull(receivedException.get());
      }
  
      /**
       * Test that when a function throws an exception this is propagated through onError.
       */
      @Test
      public void functionThrowsError() {
          Subscription s = mock(Subscription.class);
          TestFlowable w = new TestFlowable(s, "one");
          Function<Throwable, Flowable<String>> resume = new Function<Throwable, Flowable<String>>() {
  
              @Override
              public Flowable<String> apply(Throwable t1) {
                  throw new RuntimeException("exception from function");
              }
  
          };
          Flowable<String> flowable = Flowable.unsafeCreate(w).onErrorResumeNext(resume);
  
          Subscriber<String> subscriber = TestHelper.mockSubscriber();
          flowable.subscribe(subscriber);
  
          try {
              w.t.join();
          } catch (InterruptedException e) {
              fail(e.getMessage());
          }
  
          // we should get the "one" value before the error
          verify(subscriber, times(1)).onNext("one");
  
          // we should have received an onError call on the Observer since the resume function threw an exception
          verify(subscriber, times(1)).onError(any(Throwable.class));
          verify(subscriber, times(0)).onComplete();
      }
  
      @Test
      public void mapResumeAsyncNext() {
          // Trigger multiple failures
          Flowable<String> w = Flowable.just("one", "fail", "two", "three", "fail");
  
          // Introduce map function that fails intermittently (Map does not prevent this when the observer is a
          //  rx.operator incl onErrorResumeNextViaFlowable)
          w = w.map(new Function<String, String>() {
              @Override
              public String apply(String s) {
                  if ("fail".equals(s)) {
                      throw new RuntimeException("Forced Failure");
                  }
                  System.out.println("BadMapper:" + s);
                  return s;
              }
          });
  
          Flowable<String> flowable = w.onErrorResumeNext(new Function<Throwable, Flowable<String>>() {
  
              @Override
              public Flowable<String> apply(Throwable t1) {
                  return Flowable.just("twoResume", "threeResume").subscribeOn(Schedulers.computation());
              }
  
          });
  
          Subscriber<String> subscriber = TestHelper.mockSubscriber();
  
          TestSubscriber<String> ts = new TestSubscriber<>(subscriber, Long.MAX_VALUE);
          flowable.subscribe(ts);
          ts.awaitDone(5, TimeUnit.SECONDS);
  
          verify(subscriber, Mockito.never()).onError(any(Throwable.class));
          verify(subscriber, times(1)).onComplete();
          verify(subscriber, times(1)).onNext("one");
          verify(subscriber, Mockito.never()).onNext("two");
          verify(subscriber, Mockito.never()).onNext("three");
          verify(subscriber, times(1)).onNext("twoResume");
          verify(subscriber, times(1)).onNext("threeResume");
      }
  
      private static class TestFlowable implements Publisher<String> {
  
          final String[] values;
          Thread t;
  
          TestFlowable(Subscription s, String... values) {
              this.values = values;
          }
  
          @Override
          public void subscribe(final Subscriber<? super String> subscriber) {
              System.out.println("TestFlowable subscribed to ...");
              subscriber.onSubscribe(new BooleanSubscription());
              t = new Thread(new Runnable() {
  
                  @Override
                  public void run() {
                      try {
                          System.out.println("running TestFlowable thread");
                          for (String s : values) {
                              System.out.println("TestFlowable onNext: " + s);
                              subscriber.onNext(s);
                          }
                          throw new RuntimeException("Forced Failure");
                      } catch (Throwable e) {
                          subscriber.onError(e);
                      }
                  }
  
              });
              System.out.println("starting TestFlowable thread");
              t.start();
              System.out.println("done starting TestFlowable thread");
          }
  
      }
  
      @Test
      public void backpressure() {
          TestSubscriber<Integer> ts = new TestSubscriber<>();
          Flowable.range(0, 100000)
                  .onErrorResumeNext(new Function<Throwable, Flowable<Integer>>() {
  
                      @Override
                      public Flowable<Integer> apply(Throwable t1) {
                          return Flowable.just(1);
                      }
  
                  })
                  .observeOn(Schedulers.computation())
                  .map(new Function<Integer, Integer>() {
                      int c;
  
                      @Override
                      public Integer apply(Integer t1) {
                          if (c++ <= 1) {
                              // slow
                              try {
                                  Thread.sleep(500);
                              } catch (InterruptedException e) {
                                  e.printStackTrace();
                              }
                          }
                          return t1;
                      }
  
                  })
                  .subscribe(ts);
          ts.awaitDone(5, TimeUnit.SECONDS);
          ts.assertNoErrors();
      }
  
      @Test
      public void normalBackpressure() {
          TestSubscriber<Integer> ts = TestSubscriber.create(0);
  
          PublishProcessor<Integer> pp = PublishProcessor.create();
  
          pp.onErrorResumeNext(new Function<Throwable, Flowable<Integer>>() {
              @Override
              public Flowable<Integer> apply(Throwable v) {
                  return Flowable.range(3, 2);
              }
          }).subscribe(ts);
  
          ts.request(2);
  
          pp.onNext(1);
          pp.onNext(2);
          pp.onError(new TestException("Forced failure"));
  
          ts.assertValues(1, 2);
          ts.assertNoErrors();
          ts.assertNotComplete();
  
          ts.request(2);
  
          ts.assertValues(1, 2, 3, 4);
          ts.assertNoErrors();
          ts.assertComplete();
      }
  
      @Test
      public void badOtherSource() {
          TestHelper.checkBadSourceFlowable(new Function<Flowable<Integer>, Object>() {
              @Override
              public Object apply(Flowable<Integer> f) throws Exception {
                  return Flowable.error(new IOException())
                          .onErrorResumeNext(Functions.justFunction(f));
              }
          }, false, 1, 1, 1);
      }
  
  }
  