}

  @Override
  public void execute(Runnable command) {
    Preconditions.checkNotNull(command, "command must not be null!");
    delegate.execute(command);
  }

  @Override
  public ListenableScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) {
    Preconditions.checkNotNull(command, "command must not be null");
    Preconditions.checkNotNull(unit, "unit must not be null!");

    }

    @Override
    public ListenableScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) {
      return NeverScheduledFuture.create();
    }

    @Override
    public ListenableScheduledFuture<?> scheduleAtFixedRate(
        Runnable command, long initialDelay, long period, TimeUnit unit) {
      return NeverScheduledFuture.create();
    }

    @Override

  public void testScheduleRunnable() throws Exception {
    Runnable command = () -> {};

    ListenableScheduledFuture<?> future = executorService.schedule(command, Duration.ofSeconds(12));

    assertThat(future.get()).isEqualTo("schedule");
    assertThat(recordedCommand).isSameInstanceAs(command);
    assertThat(recordedTimeUnit).isEqualTo(TimeUnit.NANOSECONDS);

    @Override
    protected <T> Callable<T> wrapTask(Callable<T> callable) {
      return new WrappedCallable<T>(callable);
    }

    @Override
    protected Runnable wrapTask(Runnable command) {
      return new WrappedRunnable(command);
    }
  }

  private static final class MockExecutor implements ScheduledExecutorService {
    String lastMethodCalled = "";
    long lastInitialDelay;
    long lastDelay;

    addCallback(f, callback, directExecutor());
  }

  private class CountingSameThreadExecutor implements Executor {
    int runCount = 0;

    @Override
    public void execute(Runnable command) {
      command.run();
      runCount++;
    }
  }

  private final class MockCallback implements FutureCallback<String> {
    @Nullable private String value = null;
    @Nullable private Throwable failure = null;

 * execute}.
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
enum DirectExecutor implements Executor {
  INSTANCE;

  @Override
  public void execute(Runnable command) {
    command.run();
  }

  @Override
  public String toString() {
    return "MoreExecutors.directExecutor()";
  }

  }

  @Override
  public void execute(Runnable command) {
    Preconditions.checkNotNull(command, "command must not be null!");
    delegate.execute(command);
  }

  @Override
  public ListenableScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) {
    Preconditions.checkNotNull(command, "command must not be null");
    Preconditions.checkNotNull(unit, "unit must not be null!");

      Runnable command, long initialDelay, long period, TimeUnit unit) {
    return delegate.scheduleAtFixedRate(wrapTask(command), initialDelay, period, unit);
  }

  @Override
  public final ScheduledFuture<?> scheduleWithFixedDelay(
      Runnable command, long initialDelay, long delay, TimeUnit unit) {
    return delegate.scheduleWithFixedDelay(wrapTask(command), initialDelay, delay, unit);
  }

    @Override
    protected <T> Callable<T> wrapTask(Callable<T> callable) {
      return new WrappedCallable<T>(callable);
    }

    @Override
    protected Runnable wrapTask(Runnable command) {
      return new WrappedRunnable(command);
    }
  }

  private static final class MockExecutor implements ScheduledExecutorService {
    String lastMethodCalled = "";
    long lastInitialDelay;
    long lastDelay;

   * Executor#execute(Runnable) execute()} method is called when this service is started and
   * stopped, and should return promptly.
   */
  protected Executor executor() {
    return command -> MoreExecutors.newThread(threadNameSupplier.get(), command).start();
  }

  @Override
  public String toString() {
    return serviceName() + " [" + state() + "]";
  }

  @Override
  public final boolean isRunning() {