assertThat(future.set(1)).isTrue();
    assertSuccessful(future, 1);
  }

  /** Concrete subclass for testing. */
  private static class TestedFuture<V> extends AbstractFuture<V> {
    private static <V> TestedFuture<V> create() {
      return new TestedFuture<V>();
    }
  }

  private static final class CountingRunnable implements Runnable {
    int count;

    @Override
    public void run() {