diff --git a/tests/test_framework/phpbb_ui_test_case.php b/tests/test_framework/phpbb_ui_test_case.php
index a64e89d3b9..c17be6453b 100644
--- a/tests/test_framework/phpbb_ui_test_case.php
+++ b/tests/test_framework/phpbb_ui_test_case.php
@@ -210,6 +210,8 @@ class phpbb_ui_test_case extends phpbb_test_case
 
 		$container->register('installer.install_finish.notify_user')->setSynthetic(true);
 		$container->set('installer.install_finish.notify_user', new phpbb_mock_null_installer_task());
+		$container->register('installer.install_finish.install_extensions')->setSynthetic(true);
+		$container->set('installer.install_finish.install_extensions', new phpbb_mock_null_installer_task());
 		$container->compile();
 
 		$language = $container->get('language');