Silently handle handle eval exceptions in PolymerExpressions

pkg/polymer_expressions/test/syntax_test.dart

 // Copyright (c) 2013, 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.
 
 import 'dart:async';
 import 'dart:html';
 
+import 'package:mdv/mdv.dart' as mdv;
+import 'package:logging/logging.dart';
+import 'package:observe/observe.dart';
 import 'package:polymer_expressions/polymer_expressions.dart';
+import 'package:unittest/html_enhanced_config.dart';
 import 'package:unittest/unittest.dart';
-import 'package:unittest/html_enhanced_config.dart';
-import 'package:observe/observe.dart';
-import 'package:mdv/mdv.dart' as mdv;
 
 main() {
   mdv.initialize();
   useHtmlEnhancedConfiguration();
 
   group('PolymerExpressions', () {
     var testDiv;
 
     setUp(() {
       document.body.append(testDiv = new DivElement());
@@ skipping 25 matching lines @@
       });
     });
 
     test('should handle null collections in "in" expressions', () {
       testDiv.nodes.add(new Element.html('''
           <template id="test" bind>
             <template repeat="{{ item in items }}">
               {{ item }}
             </template>
           </template>'''));
-      query('#test')
-          ..bindingDelegate = new PolymerExpressions(globals: {'items': null})
-          ..model = null;
+      query('#test').bindingDelegate =
+          new PolymerExpressions(globals: {'items': null});
       // the template should be the only node
       expect(testDiv.nodes.length, 1);
       expect(testDiv.nodes[0].id, 'test');
     });
+
+    test('should silently handle bad variable names', () {
+      var logger = new Logger('polymer_expressions');
+      var logFuture = logger.onRecord.toList();
+      testDiv.nodes.add(new Element.html('''
+          <template id="test" bind>{{ foo }}</template>'''));
+      query('#test').bindingDelegate = new PolymerExpressions();
+      return new Future(() {
+        logger.clearListeners();
+        return logFuture.then((records) {
+          expect(records.length, 1);
+          expect(records.first.message,
+              contains('Error evaluating expression'));
+          expect(records.first.message, contains('foo'));
+        });
+      });
+    });
   });
 }
 
 class Person extends Object with ChangeNotifierMixin {
   static const _FIRST_NAME = const Symbol('firstName');
   static const _LAST_NAME = const Symbol('lastName');
   static const _ITEMS = const Symbol('items');
   static const _GET_FULL_NAME = const Symbol('getFullName');
 
   String _firstName;
@@ skipping 21 matching lines @@
   List<String> get items => _items;
 
   void set items(List<String> value) {
     _items = value;
     notifyChange(new PropertyChangeRecord(_ITEMS));
   }
 
   String toString() => "Person(firstName: $_firstName, lastName: $_lastName)";
 
 }