LibTest/collection/LinkedHashMap/LinkedHashMap.identity_A01_t01.dart

// 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 LinkedHashMap.identity()
/// Creates an insertion-ordered identity-based map.
/// Effectively a shorthand for:
/// new LinkedHashMap(equals: identical, hashCode: identityHashCode)
/// @description Checks that created hash map is equivalent of
/// new LinkedHashMap(equals: identical, hashCode: identityHashCode)
/// @author sgrekhov@unipro.ru

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

class C {
  int get hashCode => 1;
  bool operator ==(Object c) {
    return true;
  }
}

main() {
  LinkedHashMap map1 = new LinkedHashMap.identity();
  LinkedHashMap map2 = new LinkedHashMap(equals: identical,
      hashCode: identityHashCode);
  LinkedHashMap map3 = new LinkedHashMap();

  C key1 = new C();
  C key2 = new C();
  C key3 = new C();

  map1[key1] = 1;
  map1[key2] = 2;
  map1[key3] = 3;

  map2[key1] = 1;
  map2[key2] = 2;
  map2[key3] = 3;

  map3[key1] = 1;
  map3[key2] = 2;
  map3[key3] = 3;

  Expect.equals(3, map1.length);
  Expect.equals(3, map2.length);
  Expect.equals(1, map3.length);
}