1/*
2 * Copyright (C) 2007 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.common.eventbus;
18
19import com.google.common.collect.Lists;
20
21import junit.framework.TestCase;
22
23import java.util.List;
24import java.util.concurrent.Executor;
25
26/**
27 * Test case for {@link AsyncEventBus}.
28 *
29 * @author Cliff Biffle
30 */
31public class AsyncEventBusTest extends TestCase {
32  private static final String EVENT = "Hello";
33
34  /** The executor we use to fake asynchronicity. */
35  private FakeExecutor executor;
36  private AsyncEventBus bus;
37
38  @Override protected void setUp() throws Exception {
39    super.setUp();
40    executor = new FakeExecutor();
41    bus = new AsyncEventBus(executor);
42  }
43
44  public void testBasicDistribution() {
45    StringCatcher catcher = new StringCatcher();
46    bus.register(catcher);
47
48    // We post the event, but our Executor will not deliver it until instructed.
49    bus.post(EVENT);
50
51    List<String> events = catcher.getEvents();
52    assertTrue("No events should be delivered synchronously.",
53        events.isEmpty());
54
55    // Now we find the task in our Executor and explicitly activate it.
56    List<Runnable> tasks = executor.getTasks();
57    assertEquals("One event dispatch task should be queued.", 1, tasks.size());
58
59    tasks.get(0).run();
60
61    assertEquals("One event should be delivered.", 1, events.size());
62    assertEquals("Correct string should be delivered.", EVENT, events.get(0));
63  }
64
65  /**
66   * An {@link Executor} wanna-be that simply records the tasks it's given.
67   * Arguably the Worst Executor Ever.
68   *
69   * @author cbiffle
70   *
71   */
72  public static class FakeExecutor implements Executor {
73    List<Runnable> tasks = Lists.newArrayList();
74
75    @Override
76    public void execute(Runnable task) {
77      tasks.add(task);
78    }
79
80    public List<Runnable> getTasks() {
81      return tasks;
82    }
83  }
84
85}
86