Convert HashSet, LinkedHashSet to factory methods and custom implementations.

tests/corelib/set_test.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.
 
 library set_test;
 
 
 import 'package:expect/expect.dart';
 import "dart:collection";
 
 void testMain(Set create()) {
   Set set = create();
+
   testLength(0, set);
   set.add(1);
   testLength(1, set);
   Expect.isTrue(set.contains(1));
 
   set.add(1);
   testLength(1, set);
   Expect.isTrue(set.contains(1));
 
   set.remove(1);
@@ skipping 159 matching lines @@
   testLength(1, set);
 }
 
 void testLength(int length, Set set) {
   Expect.equals(length, set.length);
   (length == 0 ? Expect.isTrue : Expect.isFalse)(set.isEmpty);
   (length != 0 ? Expect.isTrue : Expect.isFalse)(set.isNotEmpty);
 }
 
 main() {
-  testMain(() => new Set());
   testMain(() => new HashSet());
+  testMain(() => new LinkedHashSet());
+  testMain(() => new HashSet(equals: identical));
+  testMain(() => new LinkedHashSet(equals: identical));
+  testMain(() => new HashSet(equals: (int a, int b) => a == b || a == -b,
+                             hashCode: (int n) => n.hashCode & (-n).hashCode,
+                             isValidKey: (n) => n is int));
+  testMain(() => new LinkedHashSet(
+      equals: (int a, int b) => a == b || a == -b,
+      hashCode: (int n) => n.hashCode & (-n).hashCode,
+      isValidKey: (n) => n is int));
 }