diff --git a/core/modules/system/tests/modules/form_test/form_test.routing.yml b/core/modules/system/tests/modules/form_test/form_test.routing.yml
index 7aaf572..bded642 100644
--- a/core/modules/system/tests/modules/form_test/form_test.routing.yml
+++ b/core/modules/system/tests/modules/form_test/form_test.routing.yml
@@ -58,7 +58,7 @@ form_test.route9:
   path: '/form-test/double-form'
   defaults:
     _title: 'Double form test'
-    _controller: '\Drupal\form_test\Controller\FormTestController::twoIdenticalFormInstances'
+    _content: '\Drupal\form_test\Controller\FormTestController::twoIdenticalFormInstances'
   requirements:
     _access: 'TRUE'