diff --git a/src/nti/externalization/tests/test_datetime.py b/src/nti/externalization/tests/test_datetime.py
index 8b284f1..2500a89 100644
--- a/src/nti/externalization/tests/test_datetime.py
+++ b/src/nti/externalization/tests/test_datetime.py
@@ -40,7 +40,7 @@ def environ_tz():
     finally:
         if tz: # pragma: no cover
             os.environ['TZ'] = tz
-        else:
+        else: # pragma: no cover
             del os.environ['TZ']
         time.tzset()