add UT for Scan function

cache/redis/redis.go

@@ -137,12 +137,12 @@ func (rc *Cache) Decr(key string) error {
 
 // ClearAll clean all cache in redis. delete this redis collection.
 func (rc *Cache) ClearAll() error {
-	c := rc.p.Get()
-	defer c.Close()
 	cachedKeys, err := rc.Scan(rc.key + ":*")
 	if err != nil {
 		return err
 	}
+	c := rc.p.Get()
+	defer c.Close()
 	for _, str := range cachedKeys {
 		if _, err = c.Do("DEL", str); err != nil {
 			return err

cache/redis/redis_test.go

@@ -15,6 +15,7 @@
 package redis
 
 import (
+	"fmt"
 	"testing"
 	"time"
 
@@ -104,3 +105,40 @@ func TestRedisCache(t *testing.T) {
 		t.Error("clear all err")
 	}
 }
+
+func TestCache_Scan(t *testing.T) {
+	timeoutDuration := 10 * time.Second
+	// init
+	bm, err := cache.NewCache("redis", `{"conn": "127.0.0.1:6379"}`)
+	if err != nil {
+		t.Error("init err")
+	}
+	// insert all
+	for i := 0; i < 10000; i++ {
+		if err = bm.Put(fmt.Sprintf("astaxie%d", i), fmt.Sprintf("author%d", i), timeoutDuration); err != nil {
+			t.Error("set Error", err)
+		}
+	}
+	// scan all for the first time
+	keys, err := bm.(*Cache).Scan(DefaultKey + ":*")
+	if err != nil {
+		t.Error("scan Error", err)
+	}
+	if len(keys) != 10000 {
+		t.Error("scan all err")
+	}
+
+	// clear all
+	if err = bm.ClearAll(); err != nil {
+		t.Error("clear all err")
+	}
+
+	// scan all for the second time
+	keys, err = bm.(*Cache).Scan(DefaultKey + ":*")
+	if err != nil {
+		t.Error("scan Error", err)
+	}
+	if len(keys) != 0 {
+		t.Error("scan all err")
+	}
+}