anchor.diff:  
   import "dart:html" as dom;
   import "dart:async" as async;
  -import "dart:js" as js;
   
   import "package:polymer/polymer.dart";
   import "package:unittest/unittest.dart";
  
positive.code:         test("change and input event", () {
            var template =
                dom.document.querySelector("#changeAndInputEventTemplate") as AutoBindingElement;
            var changeCalled = expectAsync((){}, id: "change event handler called");
            var inputCalled = expectAsync((){}, id: "input event handler called");
            var model = template.model = new MyModel()
                ..changeHandler = (e) {
                  changeCalled();
                }
                ..inputHandler = (e) {
                  inputCalled();
                };
  
            return new async.Future(() {
              var input = dom.document.querySelector("#changeAndInputEvent") as CoreInput;
  
negative.code:         test("validate number", () {
            var template =
                dom.document.querySelector("#validateNumberTemplate") as AutoBindingElement;
            var model = template.model = new MyModel()
                ..stringValue = INITIAL_VALUE
                ..inputInvalidHandler = expectAsync((dom.CustomEvent e) {}, id: "inputValidCalled")
                ..inputValidHandler = expectAsync((dom.CustomEvent e) {}, id: "inputInvalidCalled");
  
            return new async.Future(() {
              var input =
  