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.util;
  
  import static org.junit.Assert.assertEquals;
  
  import java.util.List;
  import java.util.concurrent.atomic.AtomicLong;
  
  import org.junit.Test;
  
  import io.reactivex.rxjava3.core.RxJavaTest;
  import io.reactivex.rxjava3.plugins.RxJavaPlugins;
  import io.reactivex.rxjava3.testsupport.TestHelper;
  
  public class BackpressureHelperTest extends RxJavaTest {
      @Test
      public void constructorShouldBePrivate() {
          TestHelper.checkUtilityClass(BackpressureHelper.class);
      }
  
      @Test
      public void addCap() {
          assertEquals(2L, BackpressureHelper.addCap(1, 1));
          assertEquals(Long.MAX_VALUE, BackpressureHelper.addCap(1, Long.MAX_VALUE - 1));
          assertEquals(Long.MAX_VALUE, BackpressureHelper.addCap(1, Long.MAX_VALUE));
          assertEquals(Long.MAX_VALUE, BackpressureHelper.addCap(Long.MAX_VALUE - 1, Long.MAX_VALUE - 1));
          assertEquals(Long.MAX_VALUE, BackpressureHelper.addCap(Long.MAX_VALUE, Long.MAX_VALUE));
      }
  
      @Test
      public void multiplyCap() {
          assertEquals(6, BackpressureHelper.multiplyCap(2, 3));
          assertEquals(Long.MAX_VALUE, BackpressureHelper.multiplyCap(2, Long.MAX_VALUE));
          assertEquals(Long.MAX_VALUE, BackpressureHelper.multiplyCap(Long.MAX_VALUE, Long.MAX_VALUE));
          assertEquals(Long.MAX_VALUE, BackpressureHelper.multiplyCap(1L << 32, 1L << 32));
  
      }
  
      @Test
      public void producedMore() {
          List<Throwable> list = TestHelper.trackPluginErrors();
  
          try {
              AtomicLong requested = new AtomicLong(1);
  
              assertEquals(0, BackpressureHelper.produced(requested, 2));
  
              TestHelper.assertError(list, 0, IllegalStateException.class, "More produced than requested: -1");
          } finally {
              RxJavaPlugins.reset();
          }
      }
  
      @Test
      public void producedMoreCancel() {
          List<Throwable> list = TestHelper.trackPluginErrors();
  
          try {
              AtomicLong requested = new AtomicLong(1);
  
              assertEquals(0, BackpressureHelper.producedCancel(requested, 2));
  
              TestHelper.assertError(list, 0, IllegalStateException.class, "More produced than requested: -1");
          } finally {
              RxJavaPlugins.reset();
          }
      }
  
      @Test
      public void requestProduceRace() {
          final AtomicLong requested = new AtomicLong(1);
  
          for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
  
              Runnable r1 = new Runnable() {
                  @Override
                  public void run() {
                      BackpressureHelper.produced(requested, 1);
                  }
              };
  
              Runnable r2 = new Runnable() {
                  @Override
                  public void run() {
                      BackpressureHelper.add(requested, 1);
                  }
              };
  
              TestHelper.race(r1, r2);
          }
      }
  
      @Test
      public void requestCancelProduceRace() {
          final AtomicLong requested = new AtomicLong(1);
  
          for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
  
              Runnable r1 = new Runnable() {
                  @Override
                  public void run() {
                      BackpressureHelper.produced(requested, 1);
                  }
              };
  
              Runnable r2 = new Runnable() {
                  @Override
                  public void run() {
                      BackpressureHelper.addCancel(requested, 1);
                  }
              };
  
              TestHelper.race(r1, r2);
          }
      }
  
      @Test
      public void utilityClass() {
          TestHelper.checkUtilityClass(BackpressureHelper.class);
      }
  
      @Test
      public void capped() {
          final AtomicLong requested = new AtomicLong(Long.MIN_VALUE);
  
          assertEquals(Long.MIN_VALUE, BackpressureHelper.addCancel(requested, 1));
          assertEquals(Long.MIN_VALUE, BackpressureHelper.addCancel(requested, Long.MAX_VALUE));
  
          requested.set(0);
  
          assertEquals(0, BackpressureHelper.addCancel(requested, Long.MAX_VALUE));
          assertEquals(Long.MAX_VALUE, BackpressureHelper.addCancel(requested, 1));
          assertEquals(Long.MAX_VALUE, BackpressureHelper.addCancel(requested, Long.MAX_VALUE));
  
          requested.set(0);
  
          assertEquals(0, BackpressureHelper.add(requested, Long.MAX_VALUE));
          assertEquals(Long.MAX_VALUE, BackpressureHelper.add(requested, 1));
          assertEquals(Long.MAX_VALUE, BackpressureHelper.add(requested, Long.MAX_VALUE));
  
          assertEquals(Long.MAX_VALUE, BackpressureHelper.produced(requested, 1));
          assertEquals(Long.MAX_VALUE, BackpressureHelper.produced(requested, Long.MAX_VALUE));
      }
  
      @Test
      public void multiplyCap2() {
          assertEquals(Long.MAX_VALUE, BackpressureHelper.multiplyCap(3, Long.MAX_VALUE >> 1));
  
          assertEquals(Long.MAX_VALUE, BackpressureHelper.multiplyCap(1, Long.MAX_VALUE));
      }
  }
  