Make Map.keys/values Iterables.

pkg/serialization/test/serialization_test.dart

 // Copyright (c) 2012, 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 serialization_test;
 
 import '../../unittest/lib/unittest.dart';
 import '../lib/serialization.dart';
 import '../lib/src/serialization_helpers.dart';
 import '../lib/src/mirrors_helpers.dart';
@@ skipping 174 matching lines @@
   Node n1 = new Node("1"), n2 = new Node("2"), n3 = new Node("3");
   n1.children = [n2, n3];
   n2.parent = n1;
   n3.parent = n1;
 
   test('Trace a cyclical structure', () {
     var s = new Serialization();
     var trace = new Trace(new Writer(s));
     trace.writer.trace = trace;
     trace.trace(n1);
-    var all = trace.writer.references.keys;
+    var all = trace.writer.references.keys.toSet();
     expect(all.length, 4);
     expect(all.contains(n1), isTrue);
     expect(all.contains(n2), isTrue);
     expect(all.contains(n3), isTrue);
     expect(all.contains(n1.children), isTrue);
   });
 
   test('Flatten references in a cyclical structure', () {
     var s = new Serialization();
     var w = new Writer(s);
@@ skipping 275 matching lines @@
 /** A hard-coded rule for serializing Node instances. */
 class NodeRule extends CustomRule {
   bool appliesTo(instance, _) => instance is Node;
   getState(instance) => [instance.parent, instance.name, instance.children];
   create(state) => new Node(state[1]);
   setState(Node node, state) {
     node.parent = state[0];
     node.children = state[2];
   }
 }