using unittest via package import

tests/html/url_test.dart

 // Copyright (c) 2012, 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 url_test;
-import '../../pkg/unittest/lib/unittest.dart';
-import '../../pkg/unittest/lib/html_config.dart';
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_config.dart';
 import 'dart:html';
 import 'dart:typed_data';
 
 main() {
   useHtmlConfiguration();
 
   Blob createImageBlob() {
     var canvas = new CanvasElement();
     canvas.width = 100;
     canvas.height = 100;
@@ skipping 44 matching lines @@
       img.onError.listen(expectAsync((_) {
       }));
       img.onLoad.listen((_) {
         fail('URL should not have loaded.');
       });
       img.src = url;
     });
 
   });
 }