diff --git a/gomore/15_retrier/retrier.go b/gomore/15_retrier/retrier.go
index 6801c55..e93a53b 100644
--- a/gomore/15_retrier/retrier.go
+++ b/gomore/15_retrier/retrier.go
@@ -80,7 +80,7 @@ func (r *Retrier) sleep(ctx context.Context, t <-chan time.Time) error {
 }
 
 func (r *Retrier) calcSleep(i int) time.Duration {
-	// lock unsafe rand prng
+	// lock unsafe rand prog
 	r.randMu.Lock()
 	defer r.randMu.Unlock()
 	// take a random float in the range (-r.jitter, +r.jitter) and multiply it by the base amount
diff --git a/gomore/15_retrier/retrier_test.go b/gomore/15_retrier/retrier_test.go
index aaa1d51..b19cd8d 100644
--- a/gomore/15_retrier/retrier_test.go
+++ b/gomore/15_retrier/retrier_test.go
@@ -1,3 +1,11 @@
+/*
+ * @Description: https://github.com/crazybber
+ * @Author: Edward
+ * @Date: 2020-05-11 17:43:55
+ * @Last Modified by: Edward
+ * @Last Modified time: 2020-05-11 17:43:55
+ */
+
 package retrier
 
 import (
@@ -7,7 +15,12 @@ import (
 	"time"
 )
 
-var i int
+var (
+	i      int
+	errFoo = errors.New("work cancel")
+	errBar = errors.New("work cancel 2")
+	errBaz = errors.New("work cancel 3")
+)
 
 func genWork(returns []error) func() error {
 	i = 0