LibTest/collection/Maps/putIfAbsent_A02_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 dynamic putIfAbsent(Map map, key, ifAbsent())

If key is not associated to a value, calls ifAbsent and
 updates the map by mapping key to the value returned by
  ifAbsent. Returns the value in the map.

It is an error to add or remove keys from the map during the call to ifAbsent.
  If [key] is not associated to a value, calls [ifAbsent] and
 * updates the map by mapping [key] the value returned by
 * [ifAbsent]. Returns the value in the map.
 * @description Checks that the new mapping added only if the key is not present
 * in the map. Checks the value is returned.
 * @author msyabro
 * @reviewer varlax
 */
import "../../../Utils/expect.dart";
import "dart:collection";


main() {
  int i = 1;
  
  Object putIfAbsent() {
    return i;
  }
  
  Map<String, Object> map = new Map<String, Object>();
  
  Expect.isTrue(Maps.putIfAbsent(map, "1", putIfAbsent) == 1);
  Expect.isTrue(map["1"] == 1);
  
  i = 2;
  
  Expect.isTrue( Maps.putIfAbsent(map, "1", putIfAbsent) == 1);
  Expect.isTrue(map["1"] == 1);
}