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.core;
  
  import static org.junit.Assert.*;
  
  import org.junit.Test;
  import org.reactivestreams.Publisher;
  
  import io.reactivex.rxjava3.core.ConverterTest.*;
  import io.reactivex.rxjava3.exceptions.TestException;
  
  public class TransformerTest extends RxJavaTest {
  
      @Test
      public void flowableTransformerThrows() {
          try {
              Flowable.just(1).compose(new FlowableTransformer<Integer, Integer>() {
                  @Override
                  public Publisher<Integer> apply(Flowable<Integer> v) {
                      throw new TestException("Forced failure");
                  }
              });
              fail("Should have thrown!");
          } catch (TestException ex) {
              assertEquals("Forced failure", ex.getMessage());
          }
      }
  
      @Test
      public void observableTransformerThrows() {
          try {
              Observable.just(1).compose(new ObservableTransformer<Integer, Integer>() {
                  @Override
                  public Observable<Integer> apply(Observable<Integer> v) {
                      throw new TestException("Forced failure");
                  }
              });
              fail("Should have thrown!");
          } catch (TestException ex) {
              assertEquals("Forced failure", ex.getMessage());
          }
      }
  
      @Test
      public void singleTransformerThrows() {
          try {
              Single.just(1).compose(new SingleTransformer<Integer, Integer>() {
                  @Override
                  public Single<Integer> apply(Single<Integer> v) {
                      throw new TestException("Forced failure");
                  }
              });
              fail("Should have thrown!");
          } catch (TestException ex) {
              assertEquals("Forced failure", ex.getMessage());
          }
      }
  
      @Test
      public void maybeTransformerThrows() {
          try {
              Maybe.just(1).compose(new MaybeTransformer<Integer, Integer>() {
                  @Override
                  public Maybe<Integer> apply(Maybe<Integer> v) {
                      throw new TestException("Forced failure");
                  }
              });
              fail("Should have thrown!");
          } catch (TestException ex) {
              assertEquals("Forced failure", ex.getMessage());
          }
      }
  
      @Test
      public void completableTransformerThrows() {
          try {
              Completable.complete().compose(new CompletableTransformer() {
                  @Override
                  public Completable apply(Completable v) {
                      throw new TestException("Forced failure");
                  }
              });
              fail("Should have thrown!");
          } catch (TestException ex) {
              assertEquals("Forced failure", ex.getMessage());
          }
      }
  
      // Test demos for signature generics in compose() methods. Just needs to compile.
  
      @Test
      public void observableGenericsSignatureTest() {
          A<String, Integer> a = new A<String, Integer>() { };
  
          Observable.just(a).compose(TransformerTest.<String>testObservableTransformerCreator());
      }
  
      @Test
      public void singleGenericsSignatureTest() {
          A<String, Integer> a = new A<String, Integer>() { };
  
          Single.just(a).compose(TransformerTest.<String>testSingleTransformerCreator());
      }
  
      @Test
      public void maybeGenericsSignatureTest() {
          A<String, Integer> a = new A<String, Integer>() { };
  
          Maybe.just(a).compose(TransformerTest.<String>testMaybeTransformerCreator());
      }
  
      @Test
      public void flowableGenericsSignatureTest() {
          A<String, Integer> a = new A<String, Integer>() { };
  
          Flowable.just(a).compose(TransformerTest.<String>testFlowableTransformerCreator());
      }
  
      private static <T> ObservableTransformer<A<T, ?>, B<T>> testObservableTransformerCreator() {
          return new ObservableTransformer<A<T, ?>, B<T>>() {
              @Override
              public ObservableSource<B<T>> apply(Observable<A<T, ?>> a) {
                  return Observable.empty();
              }
          };
      }
  
      private static <T> SingleTransformer<A<T, ?>, B<T>> testSingleTransformerCreator() {
          return new SingleTransformer<A<T, ?>, B<T>>() {
              @Override
              public SingleSource<B<T>> apply(Single<A<T, ?>> a) {
                  return Single.never();
              }
          };
      }
  
      private static <T> MaybeTransformer<A<T, ?>, B<T>> testMaybeTransformerCreator() {
          return new MaybeTransformer<A<T, ?>, B<T>>() {
              @Override
              public MaybeSource<B<T>> apply(Maybe<A<T, ?>> a) {
                  return Maybe.empty();
              }
          };
      }
  
      private static <T> FlowableTransformer<A<T, ?>, B<T>> testFlowableTransformerCreator() {
          return new FlowableTransformer<A<T, ?>, B<T>>() {
              @Override
              public Publisher<B<T>> apply(Flowable<A<T, ?>> a) {
                  return Flowable.empty();
              }
          };
      }
  }
  