From 7873003b75394015d694a53f4bd48c94aa95e96a Mon Sep 17 00:00:00 2001
From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Fri, 28 Nov 2025 21:05:18 +0200
Subject: [PATCH v14 2/4] Add test for multixid wraparound

Author: Andrey Borodin <amborodin@acm.org>
---
 src/test/modules/test_slru/meson.build        |  3 +-
 .../test_slru/t/002_multixact_wraparound.pl   | 50 +++++++++++++++++++
 2 files changed, 52 insertions(+), 1 deletion(-)
 create mode 100644 src/test/modules/test_slru/t/002_multixact_wraparound.pl

diff --git a/src/test/modules/test_slru/meson.build b/src/test/modules/test_slru/meson.build
index e58bbdf75ac..691b387d13f 100644
--- a/src/test/modules/test_slru/meson.build
+++ b/src/test/modules/test_slru/meson.build
@@ -38,7 +38,8 @@ tests += {
        'enable_injection_points': get_option('injection_points') ? 'yes' : 'no',
     },
     'tests': [
-      't/001_multixact.pl'
+      't/001_multixact.pl',
+      't/002_multixact_wraparound.pl'
     ],
   },
 }
diff --git a/src/test/modules/test_slru/t/002_multixact_wraparound.pl b/src/test/modules/test_slru/t/002_multixact_wraparound.pl
new file mode 100644
index 00000000000..efaf902e5e3
--- /dev/null
+++ b/src/test/modules/test_slru/t/002_multixact_wraparound.pl
@@ -0,0 +1,50 @@
+# Copyright (c) 2024-2025, PostgreSQL Global Development Group
+
+# Test multixact wraparound
+
+use strict;
+use warnings FATAL => 'all';
+
+use PostgreSQL::Test::Cluster;
+use PostgreSQL::Test::Utils;
+
+use Test::More;
+
+my ($node, $result);
+
+$node = PostgreSQL::Test::Cluster->new('mike');
+$node->init;
+$node->append_conf('postgresql.conf',
+	"shared_preload_libraries = 'test_slru'");
+
+# Set the cluster's next multitransaction to 0xFFFFFFF0.
+my $node_pgdata = $node->data_dir;
+command_ok(
+	[
+		'pg_resetwal',
+		'--multixact-ids' => '0xFFFFFFF0,0xFFFFFFF0',
+		$node_pgdata
+	],
+	"set the cluster's next multitransaction to 0xFFFFFFF0");
+command_ok(
+	[
+		'dd', 'if=/dev/zero', "of=$node_pgdata/pg_multixact/offsets/FFFF",
+		'bs=4', 'count=65536'
+	],
+	"init SLRU file");
+
+command_ok([ 'rm', "$node_pgdata/pg_multixact/offsets/0000", ],
+	"drop old SLRU file");
+
+$node->start;
+$node->safe_psql('postgres', q(CREATE EXTENSION test_slru));
+
+# Consume multixids to wrap around
+foreach my $i (1 .. 32)
+{
+	$node->safe_psql('postgres', q{SELECT test_create_multixact();});
+}
+
+$node->stop;
+
+done_testing();
-- 
2.51.2