diff --git a/app/models/test_request.rb b/app/models/test_request.rb
--- a/app/models/test_request.rb
+++ b/app/models/test_request.rb
@@ -37,9 +37,7 @@
     # since there will be only one grader grading TestRequest
     # we do not need locking (hopefully)
     
-    test_request = TestRequest.find(:first, 
-                                    :order => "created_at", 
-                                    :conditions => {:status=> Task::STATUS_INQUEUE})
+    test_request = TestRequest.where(status: Task::STATUS_INQUEUE).first
     if test_request!=nil
       test_request.status = status
       test_request.save!