diff --git a/swh/lister/debian/tests/test_tasks.py b/swh/lister/debian/tests/test_tasks.py
index bd1d0b4..a5a5d0e 100644
--- a/swh/lister/debian/tests/test_tasks.py
+++ b/swh/lister/debian/tests/test_tasks.py
@@ -1,6 +1,3 @@
-from time import sleep
-from celery.result import GroupResult
-
 from unittest.mock import patch