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.maybe;
  
  import static org.junit.Assert.*;
  import static org.mockito.Mockito.*;
  
  import java.util.List;
  import java.util.concurrent.*;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import org.junit.Test;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.functions.Supplier;
  import io.reactivex.rxjava3.observers.TestObserver;
  import io.reactivex.rxjava3.plugins.RxJavaPlugins;
  import io.reactivex.rxjava3.schedulers.Schedulers;
  import io.reactivex.rxjava3.testsupport.TestHelper;
  
  public class MaybeFromRunnableTest extends RxJavaTest {
      @Test
      public void fromRunnable() {
          final AtomicInteger atomicInteger = new AtomicInteger();
  
          Maybe.fromRunnable(new Runnable() {
              @Override
              public void run() {
                  atomicInteger.incrementAndGet();
              }
          })
              .test()
              .assertResult();
  
          assertEquals(1, atomicInteger.get());
      }
  
      @Test
      public void fromRunnableTwice() {
          final AtomicInteger atomicInteger = new AtomicInteger();
  
          Runnable run = new Runnable() {
              @Override
              public void run() {
                  atomicInteger.incrementAndGet();
              }
          };
  
          Maybe.fromRunnable(run)
              .test()
              .assertResult();
  
          assertEquals(1, atomicInteger.get());
  
          Maybe.fromRunnable(run)
              .test()
              .assertResult();
  
          assertEquals(2, atomicInteger.get());
      }
  
      @Test
      public void fromRunnableInvokesLazy() {
          final AtomicInteger atomicInteger = new AtomicInteger();
  
          final Maybe<Object> maybe = Maybe.fromRunnable(new Runnable() {
              @Override public void run() {
                  atomicInteger.incrementAndGet();
              }
          });
  
          assertEquals(0, atomicInteger.get());
  
          maybe
              .test()
              .assertResult();
  
          assertEquals(1, atomicInteger.get());
      }
  
      @Test
      public void fromRunnableThrows() {
          Maybe.fromRunnable(new Runnable() {
              @Override
              public void run() {
                  throw new UnsupportedOperationException();
              }
          })
              .test()
              .assertFailure(UnsupportedOperationException.class);
      }
  
      @SuppressWarnings("unchecked")
      @Test
      public void callable() throws Throwable {
          final int[] counter = { 0 };
  
          Maybe<Void> m = Maybe.fromRunnable(new Runnable() {
              @Override
              public void run() {
                  counter[0]++;
              }
          });
  
          assertTrue(m.getClass().toString(), m instanceof Supplier);
  
          assertNull(((Supplier<Void>)m).get());
  
          assertEquals(1, counter[0]);
      }
  
      @Test
      public void noErrorLoss() throws Exception {
          List<Throwable> errors = TestHelper.trackPluginErrors();
          try {
              final CountDownLatch cdl1 = new CountDownLatch(1);
              final CountDownLatch cdl2 = new CountDownLatch(1);
  
              TestObserver<Object> to = Maybe.fromRunnable(new Runnable() {
                  @Override
                  public void run() {
                      cdl1.countDown();
                      try {
                          cdl2.await(5, TimeUnit.SECONDS);
                      } catch (InterruptedException ex) {
                          throw new RuntimeException(ex);
                      }
                  }
              }).subscribeOn(Schedulers.single()).test();
  
              assertTrue(cdl1.await(5, TimeUnit.SECONDS));
  
              to.dispose();
  
              int timeout = 10;
  
              while (timeout-- > 0 && errors.isEmpty()) {
                  Thread.sleep(100);
              }
  
              TestHelper.assertUndeliverable(errors, 0, RuntimeException.class);
  
              assertTrue(errors.get(0).toString(), errors.get(0).getCause().getCause() instanceof InterruptedException);
          } finally {
              RxJavaPlugins.reset();
          }
      }
  
      @Test
      public void disposedUpfront() {
          Runnable run = mock(Runnable.class);
  
          Maybe.fromRunnable(run)
          .test(true)
          .assertEmpty();
  
          verify(run, never()).run();
      }
  
      @Test
      public void cancelWhileRunning() {
          final TestObserver<Object> to = new TestObserver<>();
  
          Maybe.fromRunnable(new Runnable() {
              @Override
              public void run() {
                  to.dispose();
              }
          })
          .subscribeWith(to)
          .assertEmpty();
  
          assertTrue(to.isDisposed());
      }
  }
  