tests: fixed random fail of flacky test

rhodecode/apps/repository/tests/test_repo_pullrequests.py

@@ -21,9 +21,10 b' import mock'
 import pytest
 
 import rhodecode
+from rhodecode.lib import helpers as h
 from rhodecode.lib.vcs.backends.base import MergeResponse, MergeFailureReason
 from rhodecode.lib.vcs.nodes import FileNode
-from rhodecode.lib import helpers as h
+from rhodecode.lib.ext_json import json
 from rhodecode.model.changeset_status import ChangesetStatusModel
 from rhodecode.model.db import (
     PullRequest, ChangesetStatus, UserLog, Notification, ChangesetComment, Repository)
@@ -1431,7 +1432,7 b' class TestPullrequestsView(object):'
                                          'csrf_token': csrf_token})
 
         assert response.status_int == 200
-        assert response.body == '{"response": true, "redirect_url": null}'
+        assert json.loads(response.body) == json.loads('{"response": true, "redirect_url": null}')
 
         # Make sure that after update, it won't raise 500 errors
         response = self.app.get(route_path(