anchor.diff:  
   class CommandCompletedHandler {
     FileUtils fileUtils;
  -  DateTime _expectedTimestamp;
     bool _shouldHaveRun;
   
     CommandCompletedHandler(FileUtils this.fileUtils, bool this._shouldHaveRun);
   
  -  void processCompletedTest(runner.CommandOutput output) {
  +  void processCompletedTest(CommandOutput output) {
       Expect.isTrue(output.exitCode == 0);
       Expect.isTrue(output.stderr.length == 0);
       if (_shouldHaveRun) {
  
positive.code: }
  
  Command makeCompilationCommand(String testName, FileUtils fileUtils) {
    var config = new options.OptionsParser().parse(['--timeout', '2'])[0];
    var createFileScript = Platform.script
        .resolve('skipping_dart2js_compilations_helper.dart')
        .toFilePath();
  
negative.code:       var completedHandler = new CommandCompletedHandler(fileUtils, shouldRun);
        var command = makeCompilationCommand(name, fileUtils);
        var process = new runner.RunningProcess(command, 60);
        return process.run().then((CommandOutput output) {
          completedHandler.processCompletedTest(output);
        });
      }
  