diff --git a/pkg/local_object_storage/pilorama/forest_test.go b/pkg/local_object_storage/pilorama/forest_test.go
index 94b14457..caa999f9 100644
--- a/pkg/local_object_storage/pilorama/forest_test.go
+++ b/pkg/local_object_storage/pilorama/forest_test.go
@@ -322,6 +322,10 @@ func testForestTreeAddByPath(t *testing.T, s Forest) {
 	firstID := lm[2].Child
 	testMeta(t, s, cid, treeID, firstID, lm[2].Parent, Meta{Time: lm[2].Time, Items: meta})
 
+	// TreeAddByPath must return operations in increasing time order.
+	require.True(t, lm[0].Time < lm[1].Time)
+	require.True(t, lm[1].Time < lm[2].Time)
+
 	meta[0].Value = []byte("YYY")
 	lm, err = s.TreeAddByPath(context.Background(), d, treeID, AttributeFilename, []string{"path", "to"}, meta)
 	require.NoError(t, err)