anchor.diff:  // Copyright (c) 2018, the Dart project authors.  Please see the AUTHORS file
   // for details. All rights reserved. Use of this source code is governed by a
   // BSD-style license that can be found in the LICENSE file.
  +
  +import 'dart:convert';
   
   import 'package:build/build.dart';
   import 'package:build_test/build_test.dart';
  
positive.code:       }, resolvers: AnalyzerResolvers());
      });
    });
  }
  
negative.code:               class A implements B {}
                ''',
          'a|web/main.g.dart': '''
                part of 'main.dart';
                class B {}
                ''',
        }, (resolver) async {
  