anchor.diff:  
   import 'package:async/async.dart';
   import 'package:http_multi_server/http_multi_server.dart';
  +import 'package:meta/meta.dart';
  +import 'package:package_config/discovery.dart';
  +import 'package:package_config/packages.dart';
   import 'package:path/path.dart' as p; // ignore: package_path_import
   import 'package:pool/pool.dart';
   import 'package:shelf/shelf.dart' as shelf;
  
positive.code:     );
    }
  
    Uri testUri;
  
    /// The test runner configuration.
    final Configuration _config;
  
    /// The underlying server.
    final shelf.Server _server;
  
    /// The URL for this server.
    Uri get url => _server.url;
  
negative.code:     String shellPath,
      this.updateGoldens,
    }) {
      final shelf.Cascade cascade = shelf.Cascade()
          .add(_webSocketHandler.handler)
          .add(packagesDirHandler())
  