diff --git a/context/ctxhttp/ctxhttp_test.go b/context/ctxhttp/ctxhttp_test.go
index 8089b77b..139fed43 100644
--- a/context/ctxhttp/ctxhttp_test.go
+++ b/context/ctxhttp/ctxhttp_test.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build !plan9
+
 package ctxhttp
 
 import (