assertEquals("One event should be delivered.", 1, events.size());
    assertWithMessage("Correct string should be delivered.").that(events.get(0)).isEqualTo(EVENT);
  }

  /**
   * 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 = new ArrayList<>();