001/*
002 * Copyright (C) 2008 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
005 * use this file except in compliance with the License.  You may obtain a copy
006 * of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
012 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
013 * License for the specific language governing permissions and limitations under
014 * the License.
015 */
016
017package com.google.common.util.concurrent.testing;
018
019import static com.google.common.util.concurrent.MoreExecutors.directExecutor;
020import static java.util.concurrent.TimeUnit.SECONDS;
021import static org.junit.Assert.assertThrows;
022
023import com.google.common.annotations.GwtIncompatible;
024import com.google.common.util.concurrent.ListenableFuture;
025import java.util.concurrent.CountDownLatch;
026import java.util.concurrent.ExecutionException;
027import junit.framework.Assert;
028
029/**
030 * A simple mock implementation of {@code Runnable} that can be used for testing ListenableFutures.
031 *
032 * @author Nishant Thakkar
033 * @since 10.0
034 */
035@GwtIncompatible
036public class MockFutureListener implements Runnable {
037  private final CountDownLatch countDownLatch;
038  private final ListenableFuture<?> future;
039
040  public MockFutureListener(ListenableFuture<?> future) {
041    this.countDownLatch = new CountDownLatch(1);
042    this.future = future;
043
044    future.addListener(this, directExecutor());
045  }
046
047  @Override
048  public void run() {
049    countDownLatch.countDown();
050  }
051
052  /**
053   * Verify that the listener completes in a reasonable amount of time, and Asserts that the future
054   * returns the expected data.
055   *
056   * @throws Throwable if the listener isn't called or if it resulted in a throwable or if the
057   *     result doesn't match the expected value.
058   */
059  public void assertSuccess(Object expectedData) throws Throwable {
060    // Verify that the listener executed in a reasonable amount of time.
061    Assert.assertTrue(countDownLatch.await(1L, SECONDS));
062
063    try {
064      Assert.assertEquals(expectedData, future.get());
065    } catch (ExecutionException e) {
066      throw e.getCause();
067    }
068  }
069
070  /**
071   * Verify that the listener completes in a reasonable amount of time, and Asserts that the future
072   * throws an {@code ExecutableException} and that the cause of the {@code ExecutableException} is
073   * {@code expectedCause}.
074   */
075  public void assertException(Throwable expectedCause) throws Exception {
076    // Verify that the listener executed in a reasonable amount of time.
077    Assert.assertTrue(countDownLatch.await(1L, SECONDS));
078
079    ExecutionException expected = assertThrows(ExecutionException.class, () -> future.get());
080    Assert.assertSame(expectedCause, expected.getCause());
081  }
082
083  public void assertTimeout() throws Exception {
084    // Verify that the listener does not get called in a reasonable amount of
085    // time.
086    Assert.assertFalse(countDownLatch.await(1L, SECONDS));
087  }
088}