diff --git a/muk_models_groupby_hour/tests/test_groupby.py b/muk_models_groupby_hour/tests/test_groupby.py
index 1f3cefa..c015390 100644
--- a/muk_models_groupby_hour/tests/test_groupby.py
+++ b/muk_models_groupby_hour/tests/test_groupby.py
@@ -50,7 +50,7 @@ class AttachmentTestCase(common.TransactionCase):
         result = self.attachment.read_group(
             domain=[],
             fields=['name'],
-            groupby='date:hour')
+            groupby='create_date:hour')
         _logger.warning(result)
         self.assertTrue(result)
         
\ No newline at end of file