anchor.diff:  /**
    * A library for writing dart unit tests.
    *
  - * To import this library, specify the relative path to
  - * pkg/unittest/unittest.dart.
  + * To import this library, use the pub package manager.
  + * Create a pubspec.yaml file in your project and add
  + * a dependency on unittest with the following lines:
  + *     dependencies:
  + *       unittest:
  + *         sdk: unittest
  + *         
  + * Then run 'pub install' from your project directory or using
  + * the DartEditor.
  + *         
  + * Please see [Pub Getting Started](http://pub.dartlang.org/doc)
  + * for more details about the pub package manager.
    *
    * ##Concepts##
    *
  
positive.code:  * that callback is run. A count argument can be provided to specify the number
   * of times the callback should be called (the default is 1).
   *
   *     #import('path-to-dart/pkg/unittest/unitest.dart');
   *     #import('dart:html');
   *     main() {
   *       test('calllback is executed once', () {
   *         // wrap the callback of an asynchronous call with [expectAsync0] if
   *         // the callback takes 0 arguments...
   *         window.setTimeout(expectAsync0(() {
   *           int x = 2 + 3;
   *           expect(x, equals(5));
   *         }), 0);
   *       });
   *
   *       test('calllback is executed twice', () {
   *         var callback = expectAsync0(() {
   *           int x = 2 + 3;
   *           expect(x, equals(5));
   *         }, count: 2); // <-- we can indicate multiplicity to [expectAsync0]
   *         window.setTimeout(callback, 0);
   *         window.setTimeout(callback, 0);
   *       });
   *     }
   *
  
negative.code:  * arguments or that take named parameters. (this is not implemented yet,
   * but will be coming here soon).
   *
   *     import 'package:unittest/unittest.dart';
   *     import 'dart:isolate';
   *     main() {
   *       test('callback is executed', () {
   *         // indicate ahead of time that an async callback is expected.
   *         var async = startAsync();
   *         new Timer(0, (_) {
   *           // 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();
   *         });
   *       });
   *     }
   *
   */
  library unittest;
  