}
    }
  }

  private FakeExecutor fakePool;
  private SequentialExecutor e;

  @Override
  public void setUp() {
    fakePool = new FakeExecutor();
    e = new SequentialExecutor(fakePool);
  }

  public void testConstructingWithNullExecutor_fails() {
    assertThrows(NullPointerException.class, () -> new SequentialExecutor(null));
  }

  public void testBasics() {

   * A special purpose queue/executor that dispatches listener events serially on a configured
   * executor. Each event can be added and dispatched as separate phases.
   *
   * <p>This class is very similar to {@link SequentialExecutor} with the exception that events can
   * be added without necessarily executing immediately.
   */
  private static final class PerListenerQueue<L> implements Runnable {
    final L listener;