diff --git a/lib/tests/session_manager_test.php b/lib/tests/session_manager_test.php
index f583040f609..d7c29d4dfdf 100644
--- a/lib/tests/session_manager_test.php
+++ b/lib/tests/session_manager_test.php
@@ -501,12 +501,14 @@ class session_manager_test extends \advanced_testcase {
         $record->timemodified = time() - 60*20;
         $r2 = $DB->insert_record('sessions', $record);
 
+        // Guest session still within the session timeout limit.
         $record->sid          = md5('hokus3');
         $record->userid       = $guestid;
         $record->timecreated  = time() - 60*60*60;
-        $record->timemodified = time() - 60*20;
+        $record->timemodified = time() - 60*5;
         $r3 = $DB->insert_record('sessions', $record);
 
+        // Guest session outside the session timeout limit.
         $record->sid          = md5('hokus4');
         $record->userid       = $guestid;
         $record->timecreated  = time() - 60*60*60;