diff --git a/ext/session/tests/015.phpt b/ext/session/tests/015.phpt
index f41294d8676..004bb67a9b9 100644
--- a/ext/session/tests/015.phpt
+++ b/ext/session/tests/015.phpt
@@ -6,6 +6,7 @@ use_trans_sid should not affect SID
 session.use_trans_sid=1
 session.use_cookies=0
 session.cache_limiter=
+arg_separator.output=&
 --FILE--
 <?php
 error_reporting(E_ALL);