/*
    * Copyright (C) 2007 The Guava Authors
    *
    * 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 com.google.common.eventbus;
  
  import com.google.common.collect.Lists;
  
  import junit.framework.TestCase;
  
  import java.util.List;
  import java.util.concurrent.Executor;
  
  /**
   * Test case for {@link AsyncEventBus}.
   *
   * @author Cliff Biffle
   */
  public class AsyncEventBusTest extends TestCase {
    private static final String EVENT = "Hello";
  
    /** The executor we use to fake asynchronicity. */
    private FakeExecutor executor;
    private AsyncEventBus bus;
  
    @Override protected void setUp() throws Exception {
      super.setUp();
      executor = new FakeExecutor();
      bus = new AsyncEventBus(executor);
    }
  
    public void testBasicDistribution() {
      StringCatcher catcher = new StringCatcher();
      bus.register(catcher);
  
      // We post the event, but our Executor will not deliver it until instructed.
      bus.post(EVENT);
  
      List<String> events = catcher.getEvents();
      assertTrue("No events should be delivered synchronously.",
          events.isEmpty());
  
      // Now we find the task in our Executor and explicitly activate it.
      List<Runnable> tasks = executor.getTasks();
      assertEquals("One event dispatch task should be queued.", 1, tasks.size());
  
      tasks.get(0).run();
  
      assertEquals("One event should be delivered.", 1, events.size());
      assertEquals("Correct string should be delivered.", EVENT, events.get(0));
    }
  
    /**
     * An {@link Executor} wanna-be that simply records the tasks it's given.
     * Arguably the Worst Executor Ever.
     *
     * @author cbiffle
     *
     */
    public static class FakeExecutor implements Executor {
      List<Runnable> tasks = Lists.newArrayList();
  
      @Override
      public void execute(Runnable task) {
        tasks.add(task);
      }
  
      public List<Runnable> getTasks() {
        return tasks;
      }
    }
  
  }