new file mode 100644
--- /dev/null
+++ b/userid_flags.t
@@ -0,0 +1,75 @@
+#!/usr/bin/perl
+
+# (C) Sergey Kandaurov
+# (C) Nginx, Inc.
+
+# Tests for the userid_flags directive.
+
+###############################################################################
+
+use warnings;
+use strict;
+
+use Test::More;
+
+BEGIN { use FindBin; chdir($FindBin::Bin); }
+
+use lib 'lib';
+use Test::Nginx;
+
+###############################################################################
+
+select STDERR; $| = 1;
+select STDOUT; $| = 1;
+
+my $t = Test::Nginx->new()->has(qw/http userid/);
+
+$t->write_file_expand('nginx.conf', <<'EOF');
+
+%%TEST_GLOBALS%%
+
+daemon off;
+
+events {
+}
+
+http {
+    %%TEST_GLOBALS_HTTP%%
+
+    server {
+        listen       127.0.0.1:8080;
+        server_name  localhost;
+
+        userid         on;
+        userid_name    test;
+        userid_path    /0123456789;
+        userid_domain  test.domain;
+
+        location / {
+            userid_flags samesite=strict;
+
+            location /many {
+                userid_flags httponly samesite=none secure;
+            }
+        }
+
+        location /lax {
+            userid_flags samesite=lax;
+        }
+    }
+}
+
+EOF
+
+$t->write_file('index.html', '');
+$t->write_file('lax', '');
+$t->write_file('many', '');
+$t->try_run('no userid_flags')->plan(3);
+
+###############################################################################
+
+like(http_get('/'), qr/samesite=strict/, 'strict');
+like(http_get('/lax'), qr/samesite=lax/, 'lax');
+like(http_get('/many'), qr/secure; httponly; samesite=none/, 'many');
+
+###############################################################################