Adding test for InputElement.valueAsNumber

tests/html/input_element_test.dart

 library input_element_test;
 import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_individual_config.dart';
 import 'dart:html';
 
 void check(InputElement element, String type, [bool supported = true]) {
   expect(element is InputElement, true);
   if (supported) {
     expect(element.type, type);
   } else {
@@ skipping 125 matching lines @@
       }
     });
 
     test('datetime-local', () {
       check(new LocalDateTimeInputElement(), 'datetime-local',
           LocalDateTimeInputElement.supported);
     });
 
     test('number', () {
       check(new NumberInputElement(), 'number', NumberInputElement.supported);
+      if (NumberInputElement.supported) {
+        var element = new NumberInputElement();
+        element.value = '123';
+        expect(element.valueAsNumber, 123);
+      }
     });
 
     test('range', () {
       check(new RangeInputElement(), 'range', RangeInputElement.supported);
     });
 
     test('checkbox', () {
       check(new CheckboxInputElement(), 'checkbox');
     });
 
@@ skipping 23 matching lines @@
   });
 
   group('attributes', () {
     test('valueSetNull', () {
       final e = new TextInputElement();
       e.value = null;
       expect(e.value, '');
     });
   });
 }