LibTest/async/Completer/completeError_A03_t01.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 void completeError(Object exception, [Object stackTrace])
/// Calling complete or completeError must not be done more than once.
/// @description Checks that an error is thrown if
/// the completer is already completed with a value.
/// @author msyabro
/// @reviewer kaigorodov

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

import "dart:async";

main() {
  var completer = new Completer();
  completer.complete('value');

  Expect.throws(() => completer.completeError('another value'));
}