LibTest/typed_data/Uint16List/map_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<T> map<T>(T f(E e))
/// ...
/// As long as the returned [Iterable] is not iterated over, the supplied
/// function [f] will not be invoked.
/// @description Checks that [f] is not invoked until the returned [Iterable] is
/// not iterated over.
/// @author msyabro


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

main() {
  bool invoked = false;
  int f(int e) {
    invoked = true;;
    return e;
  }

  var l = new Uint16List.fromList([1, 2, 3, 4, 5]);
  var res = l.map(f);

  Expect.isFalse(invoked);
  res.elementAt(0);
  Expect.isTrue(invoked);
}