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