anchor.diff:   *
    * Multiple tests:
    *
  - *     #import('path-to-dart/pkg/unittest/unitest.dart');
  + *     import 'package:unittest/unittest.dart';
    *     main() {
    *       test('this is a test', () {
    *         int x = 2 + 3;
  
positive.code:  * arguments or that take named parameters. (this is not implemented yet,
   * but will be coming here soon).
   *
   *     #import('path-to-dart/pkg/unittest/unitest.dart');
   *     #import('dart:html');
   *     main() {
   *       test('calllback is executed', () {
   *         // indicate ahead of time that an async callback is expected.
   *         var async = startAsync();
   *         window.setTimeout(() {
   *           // Guard the body of the callback, so errors are propagated
   *           // correctly
   *           guardAsync(() {
   *             int x = 2 + 3;
   *             expect(x, equals(5));
   *           });
   *           // indicate that the asynchronous callback was invoked.
   *           async.complete();
   *         }), 0);
   *       });
   *
   */
  library unittest;
  
negative.code:  *
   * A trivial test:
   *
   *     import 'package:unittest/unittest.dart';
   *     main() {
   *       test('this is a test', () {
   *         int x = 2 + 3;
  