diff --git a/testutils/bad_reader.go b/testutils/bad_reader.go
index ca06c5e9..f9d0aded 100644
--- a/testutils/bad_reader.go
+++ b/testutils/bad_reader.go
@@ -16,6 +16,7 @@ package testutils
 
 import "errors"
 
+// BadReader is an io.Reader which always errors
 type BadReader struct {
 	Error error
 }