LibTest/collection/Maps/putIfAbsent_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 dynamic putIfAbsent(Map map, key, 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 returned value.
 * @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);
}