anchor.diff:  
       test('prepareRequestHandler', () {
         // given
  -      HttpRequest req;
         var request = new HttpRequestMock(Uri.parse('/static/'));
   
         // when & then
  
positive.code:       // then
        requestNavigator.getLogs(callsTo('registerDefaultHandler')).verify(happenedOnce);
      });
    });
  }
  
  
negative.code:   HttpRequestMock(this.uri);
  }
  
  class StreamHttpRequestMock extends Mock implements Stream<HttpRequest> {}
  
  void main() {
    group('(Backend)', () {
      Backend backend;
  