diff --git a/src/testdir/test64.ok b/src/testdir/test64.ok
index 31052fb..40b02cd 100644
--- a/src/testdir/test64.ok
+++ b/src/testdir/test64.ok
@@ -576,6 +576,15 @@
 OK 0 - [0-9\n]\+
 OK 1 - [0-9\n]\+
 OK 2 - [0-9\n]\+
+OK 0 - \_[0-9]\+
+OK 1 - \_[0-9]\+
+OK 2 - \_[0-9]\+
+OK 0 - \_f
+OK 1 - \_f
+OK 2 - \_f
+OK 0 - \_f\+
+OK 1 - \_f\+
+OK 2 - \_f\+
 OK 0 - [0-9]
 OK 1 - [0-9]
 OK 2 - [0-9]