LibTest/collection/DoubleLinkedQueue/retainWhere_A02_t03.dart

// Copyright (c) 2016, 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.

/// @assertion void retainWhere(bool test(E element))
/// The [test] function must not throw or modify the queue.
///
/// @description Checks case when test function clears the queue
///
/// @note See https://github.com/dart-lang/sdk/issues/27920. While spec reads
/// that [test] function must not modify the queue it is expensive to check it
/// every time. So, let's test the current implementation.
/// @author iarkh@unipro.ru
/// @issue 27920

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

List list = [1, 3, 3, 4, 5, 6];
DoubleLinkedQueue? queue;

bool testClear1(var element) {
  queue?.clear();
  return element == 1;
}

bool testClear2(var element) {
  queue?.clear();
  return false;
}

bool testClear3(var element) {
  queue?.clear();
  return true;
}

check(bool test(var element), List list, List expected) {
  queue = new DoubleLinkedQueue.from(list);
  Expect.throws(() {queue?.retainWhere(test);});
}

main() {
  check(testClear1, list, []);
  check(testClear2, list, []);
  check(testClear3, list, []);
}