using unittest via package import

tests/html/css_test.dart

 library CssTest;
-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';
 
 main() {
   useHtmlIndividualConfiguration();
 
   group('supportsPointConversions', () {
     test('supported', () {
       expect(Window.supportsPointConversions, true);
     });
   });
@@ skipping 24 matching lines @@
         checkPoint(255, 200, window.convertPointFromNodeToPage(element, point));
       }, expectation);
     });
   });
 }
 
 void checkPoint(expectedX, expectedY, Point point) {
   expect(point.x.round(), equals(expectedX), reason: 'Wrong point.x');
   expect(point.y.round(), equals(expectedY), reason: 'Wrong point.y');
 }