LibTest/collection/LinkedList/singleWhere_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 E singleWhere(bool test(E value))
/// Otherwise, if there are no matching elements, or if there is more than one
/// matching element, a [StateError] is thrown.
/// @description Checks that a [StateError] is thrown if more than one element
/// match.
/// @author kaigorodov

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

check(List a0, test(value)) {
  LinkedList<MyLinkedListEntry<int>> a = toLinkedList(a0);
  bool test2(MyLinkedListEntry<int> value) =>
    test(value.value);
  Expect.throws(() { a.singleWhere(test2); }, (e) => e is StateError);
}

main() {
  check(const[1, 2, -5, -6, 1], (value) => value == 1);
  check([1, 2, -3, 4, -1], (value) => value < 0);
}