LibTest/async/Future/whenComplete_A02_t02.dart

// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

// @dart = 2.9

/// @assertion Future<T> whenComplete(action())
/// The future returned by this call, f, will complete the same way as this
/// future unless an error occurs in the action call, or in a Future returned by
/// the action call. If the call to action does not return a future, its return
/// value is ignored.
/// @description Checks that the future returned by this call, f,
/// will complete with the same error as this future, if error occurs.
/// @author a.semenov@unbipro.ru

import "dart:async";
import "../../../Utils/expect.dart";

main() {
  int value = 20;

  Completer completer = new Completer();
  Future f0 = completer.future;
  Future f = f0.whenComplete(() {});

  asyncStart();
  completer.completeError(value);

  f.then(
    (value2) {
      Expect.fail("Returned future should complete with error");
    },
    onError: (error) {
      Expect.equals(value, error);
      asyncEnd();
  });
}