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.schedulers;
  
  import static org.junit.Assert.*;
  import static org.mockito.Mockito.*;
  
  import java.util.concurrent.*;
  
  import org.junit.Test;
  
  import io.reactivex.rxjava3.core.Scheduler;
  import io.reactivex.rxjava3.core.Scheduler.Worker;
  import io.reactivex.rxjava3.disposables.Disposable;
  import io.reactivex.rxjava3.internal.functions.Functions;
  import io.reactivex.rxjava3.internal.schedulers.SingleScheduler.ScheduledWorker;
  import io.reactivex.rxjava3.plugins.RxJavaPlugins;
  import io.reactivex.rxjava3.schedulers.*;
  import io.reactivex.rxjava3.testsupport.*;
  
  public class SingleSchedulerTest extends AbstractSchedulerTests {
  
      @Test
      @SuppressUndeliverable
      public void shutdownRejects() {
          final int[] calls = { 0 };
  
          Runnable r = new Runnable() {
              @Override
              public void run() {
                  calls[0]++;
              }
          };
  
          Scheduler s = new SingleScheduler();
          s.shutdown();
  
          assertEquals(Disposable.disposed(), s.scheduleDirect(r));
  
          assertEquals(Disposable.disposed(), s.scheduleDirect(r, 1, TimeUnit.SECONDS));
  
          assertEquals(Disposable.disposed(), s.schedulePeriodicallyDirect(r, 1, 1, TimeUnit.SECONDS));
  
          Worker w = s.createWorker();
          ((ScheduledWorker)w).executor.shutdownNow();
  
          assertEquals(Disposable.disposed(), w.schedule(r));
  
          assertEquals(Disposable.disposed(), w.schedule(r, 1, TimeUnit.SECONDS));
  
          assertEquals(Disposable.disposed(), w.schedulePeriodically(r, 1, 1, TimeUnit.SECONDS));
  
          assertEquals(0, calls[0]);
  
          w.dispose();
  
          assertTrue(w.isDisposed());
      }
  
      @Test
      public void startRace() {
          final Scheduler s = new SingleScheduler();
          for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
              s.shutdown();
  
              Runnable r1 = new Runnable() {
                  @Override
                  public void run() {
                      s.start();
                  }
              };
  
              TestHelper.race(r1, r1);
          }
      }
  
      @Test
      public void runnableDisposedAsync() throws Exception {
          final Scheduler s = Schedulers.single();
          Disposable d = s.scheduleDirect(Functions.EMPTY_RUNNABLE);
  
          while (!d.isDisposed()) {
              Thread.sleep(1);
          }
      }
  
      @Test
      public void runnableDisposedAsyncCrash() throws Exception {
          final Scheduler s = Schedulers.single();
  
          Disposable d = s.scheduleDirect(new Runnable() {
              @Override
              public void run() {
                  throw new IllegalStateException();
              }
          });
  
          while (!d.isDisposed()) {
              Thread.sleep(1);
          }
      }
  
      @Test
      public void runnableDisposedAsyncTimed() throws Exception {
          final Scheduler s = Schedulers.single();
  
          Disposable d = s.scheduleDirect(Functions.EMPTY_RUNNABLE, 1, TimeUnit.MILLISECONDS);
  
          while (!d.isDisposed()) {
              Thread.sleep(1);
          }
      }
  
      @Override protected Scheduler getScheduler() {
          return Schedulers.single();
      }
  
      @Test
      public void zeroPeriodRejectedExecution() throws Throwable {
          TestHelper.withErrorTracking(errors -> {
              Scheduler s = RxJavaPlugins.createSingleScheduler(new RxThreadFactory("Test"));
              s.shutdown();
              Runnable run = mock(Runnable.class);
  
              s.schedulePeriodicallyDirect(run, 1, 0, TimeUnit.MILLISECONDS);
  
              Thread.sleep(100);
  
              verify(run, never()).run();
  
              TestHelper.assertUndeliverable(errors, 0, RejectedExecutionException.class);
          });
      }
  }
  