t/extsearch.t | 5 ++++-

diff --git a/t/extsearch.t b/t/extsearch.t
index 10b14baf19f1cfac16c5cb2aa444ab74657db878..2a1b05c769d4c67ea2d0bb813f1968962f7f543a 100644
--- a/t/extsearch.t
+++ b/t/extsearch.t
@@ -53,7 +53,10 @@
 run_script(['-index', "$home/v1test"]) or BAIL_OUT "index $?";
 
 ok(run_script([qw(-extindex --all), "$home/extindex"]), 'extindex init');
-
+{
+	my $es = PublicInbox::ExtSearch->new("$home/extindex");
+	ok($es->has_threadid, '->has_threadid');
+}
 
 { # TODO: -extindex should write this to config
 	open $fh, '>>', $cfg_path or BAIL_OUT $!;