Implement list and fix test

leveldb.go

@@ -23,12 +23,23 @@ func NewLevelDB(path string) (*LevelDB, error) {
 }
 
 func (ldb *LevelDB) List(ns []string, limits ...string) ([]string, error) {
+	namespace := resolveNamespace(ns)
+	limits = resolveLimits(limits)
+	limits[0] = path.Join(namespace, limits[0])
+	limits[1] = path.Join(namespace, limits[1])
+
 	keys := []string{}
-	r := util.BytesPrefix([]byte{})
+	r := util.BytesPrefix([]byte(namespace))
 	it := ldb.db.NewIterator(r, nil)
 	defer it.Release()
 	for it.Next() {
-		keys = append(keys, string(it.Key()))
+		k := string(it.Key())
+		if k < limits[0] {
+			continue
+		} else if k > limits[1] {
+			break
+		}
+		keys = append(keys, k)
 	}
 	err := it.Error()
 	return keys, err