LibTest/core/Runes/map_A03_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 map(f(E element))
/// The transformed elements will not be cached. Iterating multiple times
/// over the returned [Iterable] will invoke the supplied
/// function [f] multiple times on the same element.
/// @description Checks that [f] will be invoked every time
/// [Iterable] is iterated.
/// @author msyabro

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

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

  var runes = new Runes('string');
  var res = runes.map(f);

  res.elementAt(0);
  Expect.equals(1, count);

  res.elementAt(0);
  Expect.equals(2, count);

  res.elementAt(3);
  Expect.equals(3, count);

  res.elementAt(3);
  Expect.equals(4, count);

  res.elementAt(1);
  Expect.equals(5, count);
}