anchor.diff:  
       test('escape2', () {
         expect(HttpServer.bind('localhost', 0).then((server) {
  -        var dir = new Directory('').createTempSync();
  +        var dir = Directory.systemTemp.createTempSync('http_server_virtual_');
           new Directory('${dir.path}/dir').createSync();
           var virDir = new VirtualDirectory(dir.path);
           virDir.allowDirectoryListing = true;
  
positive.code:   group('escape-root', () {
      test('escape1', () {
        expect(HttpServer.bind('localhost', 0).then((server) {
          var dir = new Directory('').createTempSync();
          var virDir = new VirtualDirectory(dir.path);
          virDir.allowDirectoryListing = true;
  
  
negative.code: 
        test('dirs', () {
          expect(HttpServer.bind('localhost', 0).then((server) {
            var dir = Directory.systemTemp.createTempSync('http_server_virtual_');
            var virDir = new VirtualDirectory(dir.path);
            for (int i = 0; i < 10; i++) {
              new Directory('${dir.path}/$i').createSync();
  