verifyGetOnPendingFuture(future);
    verifyTimedGetOnPendingFuture(future);

    assertThrows(IllegalStateException.class, future::resultNow);
    assertThrows(IllegalStateException.class, future::exceptionNow);
  }

  private static void assertSuccessful(
      AbstractFuture<@Nullable Integer> future, @Nullable Integer expectedResult)
      throws InterruptedException, TimeoutException, ExecutionException {

    verifyGetOnPendingFuture(future);
    verifyTimedGetOnPendingFuture(future);

    assertThrows(IllegalStateException.class, future::resultNow);
    assertThrows(IllegalStateException.class, future::exceptionNow);
  }

  private static void assertSuccessful(
      AbstractFuture<@Nullable Integer> future, @Nullable Integer expectedResult)
      throws InterruptedException, TimeoutException, ExecutionException {

    }

    @Override
    @ParametricNullness
    public final V resultNow() {
      return super.resultNow();
    }

    @Override
    public final Throwable exceptionNow() {
      return super.exceptionNow();
    }
  }

  /** Listeners form a Treiber stack through the {@link #listeners} field. */
  static final class Listener {
    static final Listener TOMBSTONE = new Listener();