LibTest/core/Runes/takeWhile_A02_t01.dart

// Copyright (c) 2013, 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<E> takeWhile(bool test(E element))
/// The filtering happens lazily.
/// @description Checks that [test] is not invoked until returned
/// [Iterable] is not iterated.
/// @author msyabro

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

main() {
  var count = 0;
  test(e) {
    ++count;
    return true;
  }

  var runes = new Runes('abc');
  var res = runes.takeWhile(test);
  Expect.equals(0, count);
  res.elementAt(0);
  Expect.equals(1, count);
}