LibTest/collection/DoubleLinkedQueue/isNotEmpty_A02_t01.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.

// @dart = 2.9

/// @assertion final bool isNotEmpty
/// May be computed by checking if [iterator.moveNext()] returns [true].
/// @description Checks that method returns true only if queue is not empty.
/// @author iarkh@unipro.ru

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

main() {
  DoubleLinkedQueue list = new DoubleLinkedQueue();
  Expect.equals(list.isNotEmpty, list.iterator.moveNext());
  list.addLast(1);
  Expect.equals(list.isNotEmpty, list.iterator.moveNext());
  list.addFirst(1);
  Expect.equals(list.isNotEmpty, list.iterator.moveNext());
  list.removeFirst();
  Expect.equals(list.isNotEmpty, list.iterator.moveNext());
  list.removeFirst();
  Expect.equals(list.isNotEmpty, list.iterator.moveNext());
}