diff --git a/shadowsocks/manager.py b/shadowsocks/manager.py
index 7093ad8..7883b10 100644
--- a/shadowsocks/manager.py
+++ b/shadowsocks/manager.py
@@ -213,7 +213,7 @@ def test():
         enc.append(manager)
         manager.run()
 
-    t = threading.Thread(target=run_server).start()
+    threading.Thread(target=run_server).start()
     time.sleep(2)
     manager = enc[0]
     cli = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)