LibTest/collection/DoubleLinkedQueue/singleWhere_A01_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.

/// @assertion abstract E singleWhere(bool test(E value))
/// Returns the single element that satisfies [test].
/// Checks all elements to see if [test(element)] returns [true].
/// @description Checks that the single element that satisfies the given
/// predicate [test]
/// is returned.
/// @author kaigorodov

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

check(List a, bool test(value), int expected) {
  DoubleLinkedQueue queue = new DoubleLinkedQueue.from(a);
  int actual = queue.singleWhere(test) as int;
  Expect.equals(expected, actual);
}

main() {
  check([1, 2, -3, 0], (value) => value > 1, 2);
  check(const[1, 2, -5, -6], (value) => value == 1, 1);
}