diff --git a/tests/test_issues_server.py b/tests/test_issues_server.py
index 70a340f3653b734fa32312b268f3715c17cacbd6..4a423731fa83aa587fc44429ead3d322184e51d1 100644
--- a/tests/test_issues_server.py
+++ b/tests/test_issues_server.py
@@ -24,6 +24,7 @@
 
 """Tests for issues on gitlab.com, project caosdb-server."""
 
+import math
 import os
 import tempfile
 import time