using unittest via package import

tests/html/typing_test.dart

 library TypingTest;
-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();
 
   var isStyleSheetList =
       predicate((x) => x is List<StyleSheet>, 'is a List<StyleSheet>');
 
   test('NodeList', () {
     List<Node> asList = window.document.queryAll('body');
@@ skipping 14 matching lines @@
     // Check it's Iterable.
     int counter = 0;
     for (StyleSheet styleSheet in window.document.styleSheets) {
       counter++;
     }
 
     // There is one style sheet from the unittest framework.
     expect(counter, 1);
   });
 }