fix lint (#108)

diff --git a/test/tokenizer_test.dart b/test/tokenizer_test.dart
index 59dd2aa..ccb9d8c 100644
--- a/test/tokenizer_test.dart
+++ b/test/tokenizer_test.dart
@@ -5,15 +5,17 @@
 import 'dart:convert';
 import 'dart:io';
 import 'dart:mirrors';
-import 'package:path/path.dart' as pathos;
-import 'package:test/test.dart';
+
 import 'package:html/src/token.dart';
 import 'package:html/src/tokenizer.dart';
+import 'package:path/path.dart' as pathos;
+import 'package:test/test.dart';
+
 import 'support.dart';
 
 class TokenizerTestParser {
-  String _state;
-  String _lastStartTag;
+  final String _state;
+  final String _lastStartTag;
   List outputTokens;
 
   TokenizerTestParser(String initialState, [String lastStartTag])