diff --git a/test_threading.py b/test_threading.py
index 0e9cc1f..6a34328 100644
--- a/test_threading.py
+++ b/test_threading.py
@@ -26,7 +26,7 @@ class Aclass(threading.Thread):
             time.sleep(1)
 
     def stop(self):
-        sys.exit()
+        self.running = False
 
 
 class dev():