Upgrade to test 0.12.0.

test/parse_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library parse_test;
 
-import 'package:unittest/unittest.dart';
+import 'package:test/test.dart';
 import 'package:args/args.dart';
 import 'utils.dart';
 
 void main() {
   group('ArgParser.parse()', () {
     test('does not destructively modify the argument list', () {
       var parser = new ArgParser();
       parser.addFlag('verbose');
 
       var args = ['--verbose'];
@@ skipping 477 matching lines @@
         var parser = new ArgParser();
         parser.addFlag('woof');
 
         var results = parser.parse(['--woof', 'stop', '--', 'arg']);
         expect(results['woof'], isTrue);
         expect(results.rest, equals(['stop', '--', 'arg']));
       });
     });
   });
 }