LibTest/collection/LinkedListEntry/LinkedListEntry_class_A03_t01.dart

// Copyright (c) 2017, 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 class LinkedListEntry<E extends LinkedListEntry
/// An entry can be in at most one linked list at a time. While an entry is in a
/// linked list, the [list] property points to that linked list, and otherwise
/// the [list] property is [null].
/// When created, an entry is not in any linked list.
/// @description Checks that [LinkedListEntry] element can belong to only one
/// linked list at a time.
/// @author iarkh@unipro.ru

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

main() {
  LinkedList<MyLinkedListEntry<int>> list1 =
      new LinkedList<MyLinkedListEntry<int>>();
  LinkedList<MyLinkedListEntry> list2 =
      new LinkedList<MyLinkedListEntry<int>>();

  MyLinkedListEntry<int> entry = new MyLinkedListEntry<int>(1);
  Expect.isNull(entry.list);

  list1.add(entry);
  Expect.throws(() {
    list2.add(entry);
  });
  Expect.throws(() {
    list1.add(entry);
  });
  Expect.equals(list1, entry.list);
  Expect.isTrue(list1.contains(entry));

  list1.remove(entry);
  Expect.isNull(entry.list);
  Expect.isFalse(list1.contains(entry));

  list2.add(entry);
  Expect.throws(() {
    list2.add(entry);
  });
  Expect.throws(() {
    list1.add(entry);
  });
  Expect.equals(list2, entry.list);
  Expect.isTrue(list2.contains(entry));
  Expect.isFalse(list1.contains(entry));
}