anchor.diff:    http_testing.MockClient client;
   
     MockClient(String hostname, String rootPath)
  -      : hostname = hostname,
  -        rootPath = rootPath,
  +      : rootPath = rootPath,
           rootUri = Uri.parse('https://$hostname$rootPath') {
       client = http_testing.MockClient(handler);
     }
  
positive.code:   }
  
    Future<http.Response> handler(http.Request request) {
      expect(request.url.host, hostname);
      var path = request.url.path;
      if (mocks[request.method] == null) {
        throw 'No mock handler for method ${request.method} found. '
  
negative.code: 
    final _bytesHeaderRegexp = RegExp(r'bytes=(\d+)-(\d+)');
  
    final String rootPath;
    final Uri rootUri;
  
  