fix tests and double namespacing depending on backend

cache.go

@@ -3,6 +3,7 @@ package storage
 import (
 	"os"
 	"path"
+	"strings"
 	"time"
 
 	cache "github.com/patrickmn/go-cache"
@@ -34,7 +35,7 @@ func (c *Cache) List(ns []string, limits ...string) ([]string, error) {
 	keys := []string{}
 	for k := range m {
 		if k >= limits[0] && k <= limits[1] {
-			keys = append(keys, k)
+			keys = append(keys, strings.TrimPrefix(k, namespace+"/"))
 		}
 	}
 	return keys, nil