diff --git a/hphp/test/slow/ext_session/ext_session.php b/hphp/test/slow/ext_session/ext_session.php
index 23d4f002f125c..ffa0cdaa77150 100644
--- a/hphp/test/slow/ext_session/ext_session.php
+++ b/hphp/test/slow/ext_session/ext_session.php
@@ -4,6 +4,7 @@
 var_dump(session_get_cookie_params());
 var_dump(session_name("name1"));
 var_dump(session_name("name2"));
+var_dump(session_id());
 
 session_start();
 session_destroy();
diff --git a/hphp/test/slow/ext_session/ext_session.php.expect b/hphp/test/slow/ext_session/ext_session.php.expect
index fe85a15454d0a..1e8bd2bea71e3 100644
--- a/hphp/test/slow/ext_session/ext_session.php.expect
+++ b/hphp/test/slow/ext_session/ext_session.php.expect
@@ -12,3 +12,4 @@ array(5) {
 }
 string(9) "PHPSESSID"
 string(5) "name1"
+string(0) ""