using unittest via package import

tests/html/audioelement_test.dart

 library AudioElementTest;
-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';
 
 main() {
   useHtmlConfiguration();
 
   test('constructorTest1', () {
       var audio = new AudioElement();
       expect(audio, isNotNull);
       expect(audio is AudioElement, isTrue);
     });
 
   test('constructorTest2', () {
       var audio = new AudioElement('hahaURL');
       expect(audio, isNotNull);
       expect(audio is AudioElement, isTrue);
       expect(audio.src, contains('hahaURL'));
     });
 }