update elements and fix some bugs

test/paper_badge_test.dart

 // Copyright (c) 2015, 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.
 @TestOn('browser')
 library polymer_elements.test.paper_badge_test;
 
 import 'dart:async';
 import 'dart:html';
 import 'package:polymer_elements/paper_badge.dart';
 import 'package:web_components/web_components.dart';
 import 'package:test/test.dart';
 import 'common.dart';
 
 main() async {
   await initWebComponents();
 
   group('basic', () {
     test('badge is positioned correctly', () {
       DivElement f = fixture('basic');
       PaperBadge badge = f.querySelector('paper-badge');
       HtmlElement actualbadge = badge.querySelector('#badge');
       expect(actualbadge.text, equals("1"));
+      expect(badge.target.getAttribute('id'), 'target');
       badge.updatePosition();
 
       Completer done = new Completer();
 
       wait(1).then((_) {
         Rectangle divRect = f.querySelector('#target').getBoundingClientRect();
         expect(divRect.width, equals(100));
         expect(divRect.height, equals(20));
 
         Rectangle contentRect = badge.getBoundingClientRect();
         expect(contentRect.width, equals(22));
         expect(contentRect.height, equals(22));
         // The target div is 100 x 20, and the badge is centered on the
         // top right corner.
         expect(contentRect.left, equals(100 - 11));
         expect(contentRect.top, equals(0 - 11));
         // Also check the math, just in case.
         expect(contentRect.left, equals(divRect.width - 11));
         expect(contentRect.top, equals(divRect.top - 11));
         done.complete();
       });
 
       return done.future;
     });
     test('badge is positioned correctly after being dynamically set', () {
       DivElement f = fixture('dynamic');
       PaperBadge badge = f.querySelector('paper-badge');
       badge.updatePosition();
 
+      expect(badge.target.getAttribute('id'), isNot('target'));
+
       Completer done = new Completer();
 
       wait(1).then((_) {
         Rectangle contentRect = badge.getBoundingClientRect();
         expect(contentRect.left, isNot(100 - 11));
         badge.forId = 'target';
+        expect(badge.target.getAttribute('id'), 'target');
         badge.updatePosition();
 
         wait(1).then((_) {
           Rectangle divRect =
               f.querySelector('#target').getBoundingClientRect();
           expect(divRect.width, equals(100));
           expect(divRect.height, equals(20));
 
           Rectangle contentRect = badge.getBoundingClientRect();
           expect(contentRect.width, equals(22));
           expect(contentRect.height, equals(22));
           // The target div is 100 x 20, and the badge is centered on the
           // top right corner.
           expect(contentRect.left, equals(100 - 11));
           expect(contentRect.top, equals(0 - 11));
           // Also check the math, just in case.
           expect(contentRect.left, equals(divRect.width - 11));
           expect(contentRect.top, equals(divRect.top - 11));
           done.complete();
         });
       });
 
       return done.future;
     });
   });
+  
+  test('badge is positioned correctly when nested in a target element', () async {
+    var f = fixture('nested');
+    var badge = f.querySelector('paper-badge');
+
+    expect(badge.target.getAttribute('id'), 'target');
+
+    badge.updatePosition();
+
+    await wait(1);
+    var divRect = f.querySelector('#target').getBoundingClientRect();
+    expect(divRect.width, 100);
+    expect(divRect.height, 20);
+
+    var contentRect = badge.getBoundingClientRect();
+    expect(contentRect.width, 22);
+    expect(contentRect.height, 22);
+
+    // The target div is 100 x 20, and the badge is centered on the
+    // top right corner.
+    expect(contentRect.left, 100 - 11);
+    expect(contentRect.top, 0 - 11);
+
+    // Also check the math, just in case.
+    expect(contentRect.left, divRect.width - 11);
+    expect(contentRect.top, divRect.top - 11);
+  });
 
   group('badge is inside a custom element', () {
     test('badge is positioned correctly', () {
       HtmlElement f = fixture('custom');
 
       PaperBadge badge = f.querySelector('paper-badge');
       HtmlElement actualbadge = badge.querySelector('#badge');
       expect(actualbadge.text, equals("1"));
       badge.updatePosition();
 
@@ skipping 13 matching lines @@
         expect(contentRect.top, equals(0 - 11));
         // Also check the math, just in case.
         expect(contentRect.left, equals(divRect.width - 11));
         expect(contentRect.top, equals(divRect.top - 11));
 
         done.complete();
       });
     });
   });
 }