anchor.diff:    Expect.isTrue(compilationResult.isSuccess);
     List<String> scriptD8Command = [
       'sdk/lib/_internal/js_runtime/lib/preambles/d8.js',
  -    'js.js'
  +    outputFile
     ];
     ProcessResult result = runD8AndStep(dir.path, annotatedCode, scriptD8Command);
     List<String> d8output = result.stdout.split("\n");
  
positive.code:     d8output.forEach(print);
    }
    checkD8Steps(dir.path, d8output, annotatedCode, debug: debug);
  }
  
negative.code:     {bool debug: false,
      bool verbose: false,
      List<String> options: const <String>[]}) async {
    Directory dir = Directory.systemTemp.createTempSync('stepping_test');
    String path = dir.path;
    String inputFile = '$path/test.dart';
    new File(inputFile).writeAsStringSync(annotatedCode.sourceCode);
    String outputFile = '$path/js.js';
    List<String> arguments = <String>[
      '--out=$outputFile',
      inputFile,
      Flags.disableInlining,
    ];
    if (config == kernelMarker) {
  