diff --git a/tests/test_units/test_dataio.py b/tests/test_units/test_dataio.py
index b2f2a2b87..95aaf6798 100644
--- a/tests/test_units/test_dataio.py
+++ b/tests/test_units/test_dataio.py
@@ -1,4 +1,4 @@
-"""Test the dataio ExportData etc from the dataio.py module"""
+"""Test the dataio ExportData etc from the dataio.py module."""
 import logging
 import os
 import pathlib