anchor.diff:    await d.file('pubspec.yaml', r'''
   name: peanut_test
   
  +environment:
  +  sdk: '>=2.10.0 <3.0.0'
  +
   dev_dependencies:
     build_runner: '>=0.8.10 <2.0.0'
     build_web_compilers: '>=1.0.0 <3.0.0'
  
positive.code:   }
  }
  
  final _exampleFiles = Map.fromEntries(Directory('example')
      .listSync()
      .cast<File>()
      .map((f) => MapEntry(p.basename(f.path), f.readAsStringSync())));
  
  Future _logGitTree(GitDir gitDir, String sha, {int depth = 0}) async {
    final treeContents = await gitDir.lsTree(sha);
  
negative.code:       await _initGitDir();
  
        await expectLater(
          _run(options: const Options(postBuildDartScript: 'post_build.dart')),
          _throwsPeanutException(startsWith(
            'The provided post-build Dart script does not exist '
            'or is not a file.',
          )),
        );
      });
  
      test('failed', () async {
  