diff --git a/testing/servers/udp/udp.go b/testing/servers/udp/udp.go
index 8acf28798..94ce46c6b 100644
--- a/testing/servers/udp/udp.go
+++ b/testing/servers/udp/udp.go
@@ -2,6 +2,7 @@ package udp
 
 import (
 	"fmt"
+
 	"v2ray.com/core/common/net"
 )