diff --git a/expression/integration_test.go b/expression/integration_test.go
index 540a56bfde261..334a61ff1e308 100755
--- a/expression/integration_test.go
+++ b/expression/integration_test.go
@@ -1,5 +1,4 @@
 // Copyright 2017 PingCAP, Inc.
-// Copyright 2017 PingCAP, Inc.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.