using unittest via package import

tests/html/transition_event_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
 
 library transition_event_test;
-import '../../pkg/unittest/lib/unittest.dart';
-import '../../pkg/unittest/lib/html_individual_config.dart';
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_individual_config.dart';
 import 'dart:html';
 import 'dart:async';
 
 main() {
   useHtmlIndividualConfiguration();
 
   group('supported', () {
     test('supported', () {
       expect(CssStyleDeclaration.supportsTransitions, true);
     });
@@ skipping 16 matching lines @@
             expect(e is TransitionEvent, isTrue);
             expect(e.propertyName, 'opacity');
           }));
 
           element.style.opacity = '1';
         }));
       }
     });
   });
 }