Make html lists print a nice toString method.

tests/html/element_test.dart

 // Copyright (c) 2011, 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 ElementTest;
 import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_individual_config.dart';
 import 'dart:async';
 import 'dart:html';
 import 'dart:svg' as svg;
@@ skipping 598 matching lines @@
     testUnsupported('removeRange', () => getQueryAll().removeRange(0, 1));
 
     testUnsupported('insertangeRange', () => getQueryAll().insertRange(0, 1));
 
     testUnsupported('clear', () => getQueryAll().clear());
 
     testUnsupported('removeLast', () => getQueryAll().removeLast());
   });
 
   group('functional', () {
+    test('toString', () {
+      final elems = makeElementWithChildren().children;
+      expect(elems.toString(), "[BR, IMG, INPUT]");
+      final elem = makeElement().children;
+      expect(elem.toString(), '[]');
+    });
+
     test('scrollIntoView', () {
       var child = new DivElement();
       document.body.append(child);
 
       child.scrollIntoView(ScrollAlignment.TOP);
       child.scrollIntoView(ScrollAlignment.BOTTOM);
       child.scrollIntoView(ScrollAlignment.CENTER);
       child.scrollIntoView();
     });
   });
 
   group('_ElementList', () {
     List<Element> makeElList() => makeElementWithChildren().children;
 
     test('where', () {
       var filtered = makeElList().where((n) => n is ImageElement);
       expect(filtered.length, 1);
       expect(filtered.first, isImageElement);
       expect(filtered, isElementIterable);
     });
 
     test('sublist', () {
       var range = makeElList().sublist(1, 3);
       expect(range, isElementList);
       expect(range[0], isImageElement);
       expect(range[1], isInputElement);
     });
   });
 }