diff --git a/piker/config.py b/piker/config.py
index c11ca3f1..b1b2eedc 100644
--- a/piker/config.py
+++ b/piker/config.py
@@ -79,7 +79,7 @@ def get_app_dir(app_name, roaming=True, force_posix=False):
     # outside of the users filesystem 
     if "pytest" in sys.modules:
         log.info("TESTING")
-        os.path.join(app_name, TEST_CONFIG_DIR_PATH)
+        app_name = os.path.join(app_name, TEST_CONFIG_DIR_PATH)
 
     # if WIN:
     if platform.system() == 'Windows':