snapshot: add Close()

Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>

metadata/snapshot.go

@@ -724,3 +724,8 @@ func (s *snapshotter) pruneBranch(ctx context.Context, node *treeNode) error {
 
 	return nil
 }
+
+// Close closes s.Snapshotter but not db
+func (s *snapshotter) Close() error {
+	return s.Snapshotter.Close()
+}

metadata/snapshot_test.go

@@ -31,6 +31,9 @@ func newTestSnapshotter(ctx context.Context, root string) (snapshot.Snapshotter,
 	sn := NewDB(db, nil, map[string]snapshot.Snapshotter{"naive": snapshotter}).Snapshotter("naive")
 
 	return sn, func() error {
+		if err := sn.Close(); err != nil {
+			return err
+		}
 		return db.Close()
 	}, nil
 }