diff --git a/circuitbreaker/util_test.go b/circuitbreaker/util_test.go
index b5c0391..8d5d7b1 100644
--- a/circuitbreaker/util_test.go
+++ b/circuitbreaker/util_test.go
@@ -67,7 +67,7 @@
 
 type mock struct {
 	through int
-	err  error
+	err     error
 }
 
 func (m *mock) endpoint(context.Context, interface{}) (interface{}, error) {