diff --git a/test/unit/webapps/test_config_values.py b/test/unit/webapps/test_config_values.py
index 8a2aeae55f48..96f2c065603b 100644
--- a/test/unit/webapps/test_config_values.py
+++ b/test/unit/webapps/test_config_values.py
@@ -1,6 +1,7 @@
 import os
 from collections import namedtuple
 from datetime import timedelta
+from unittest.mock import patch
 
 import pytest
 
@@ -225,8 +226,8 @@ def get_expected_object_store_store_by(self, value):
         return 'uuid'
 
 
+@patch('galaxy.config.GalaxyAppConfiguration._override_tempdir', lambda a, b: None)
 def get_config_data():
-    config.GalaxyAppConfiguration._override_tempdir = lambda a, b: None  # method must be mocked
     configuration = config.GalaxyAppConfiguration()
     ev = ExpectedValues(configuration)
     items = ((k, v) for k, v in configuration.schema.app_schema.items())