LibTest/collection/DoubleLinkedQueue/expand_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 Iterable expand(Iterable f(E element))
/// Expands each element of this [Iterable] into zero or more elements.
/// The resulting [Iterable] runs through the elements returned by [f] for each
/// element of this, in order.
/// @description Checks that the method expands each element of this Iterable
/// into zero or more elements.
/// @author kaigorodov

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

main() {
  DoubleLinkedQueue queue = new DoubleLinkedQueue();
  
  for (int k = 0; k < 10; k++) {
    Expect.equals(0, queue.expand((element) => []).length);
    Expect.equals(k, queue.expand((element) => [element]).length);
    Expect.equals(2 * k, queue.expand((element) => [element, element]).length);
    queue.add(k);
  }
}