anchor.diff:  
   library validator_test;
   
  +import 'dart:async';
   import 'dart:io';
  -import 'dart:json';
  +import 'dart:json' as json;
   
   import 'test_pub.dart';
   import '../../../pkg/unittest/lib/unittest.dart';
  
positive.code:             expect(request.method, equals("GET"));
              expect(request.url.path, equals("/packages/foo.json"));
  
              return new Future.immediate(new http.Response(JSON.stringify({
                "name": "foo",
                "uploaders": ["nweiz@google.com"],
                "versions": ["3.0.0-pre", "2.0.0", "1.0.0"]
  
negative.code:             libPubspec("test_pkg", "1.0.0", [
                {'hosted': 'foo'}
              ]),
              file("pubspec.lock", json.stringify({
                'packages': {
                  'bar': {
                    'version': '1.2.3',
  