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 org.junit.Test;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.functions.*;
  import io.reactivex.rxjava3.observable.ObservableCovarianceTest.*;
  
  public class ObservableCombineLatestTests extends RxJavaTest {
      /**
       * This won't compile if super/extends isn't done correctly on generics.
       */
      @Test
      public void covarianceOfCombineLatest() {
          Observable<HorrorMovie> horrors = Observable.just(new HorrorMovie());
          Observable<CoolRating> ratings = Observable.just(new CoolRating());
  
          Observable.<Movie, CoolRating, Result> combineLatest(horrors, ratings, combine).blockingForEach(action);
          Observable.<Movie, CoolRating, Result> combineLatest(horrors, ratings, combine).blockingForEach(action);
          Observable.<Media, Rating, ExtendedResult> combineLatest(horrors, ratings, combine).blockingForEach(extendedAction);
          Observable.<Media, Rating, Result> combineLatest(horrors, ratings, combine).blockingForEach(action);
          Observable.<Media, Rating, ExtendedResult> combineLatest(horrors, ratings, combine).blockingForEach(action);
  
          Observable.<Movie, CoolRating, Result> combineLatest(horrors, ratings, combine);
      }
  
      BiFunction<Media, Rating, ExtendedResult> combine = new BiFunction<Media, Rating, ExtendedResult>() {
          @Override
          public ExtendedResult apply(Media m, Rating r) {
              return new ExtendedResult();
          }
      };
  
      Consumer<Result> action = new Consumer<Result>() {
          @Override
          public void accept(Result t1) {
              System.out.println("Result: " + t1);
          }
      };
  
      Consumer<ExtendedResult> extendedAction = new Consumer<ExtendedResult>() {
          @Override
          public void accept(ExtendedResult t1) {
              System.out.println("Result: " + t1);
          }
      };
  }
  