anchor.diff:      });
     });
     group('progress', () {
  -    Matcher isProgressFrame({required String parser, required int position}) =>
  -        isA<ProgressFrame>()
  -            .having(
  -                (frame) => frame.parser.toString(), 'parser', contains(parser))
  -            .having((frame) => frame.context.position, 'position', position)
  -            .having((frame) => frame.toString(), 'toString',
  -                allOf(startsWith('*' * (position + 1)), contains(parser)));
  -
       test('success', () {
         final frames = <ProgressFrame>[];
         final parser = progress(identifier, output: frames.add);
  
positive.code: import 'package:test/test.dart';
  
  final identifier = letter() & word().star();
  
  void main() {
    group('trace', () {
  
negative.code:     });
    });
    group('profile', () {
      test('success', () {
        final frames = <ProfileFrame>[];
        final parser = profile(identifier, output: frames.add);
  