// Copyright (c) 2016, 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 K firstKey()
 * Returns [null] if the map is empty.
 * @description Checks that [null] is returned if map is empty
 * @author sgrekhov@unipro.ru
 */
import "dart:collection";
import "../../../Utils/expect.dart";

main() {
  SplayTreeMap map = new SplayTreeMap();
  Expect.isNull(map.firstKey());
}