diff --git a/core/tests/Drupal/Tests/Composer/Plugin/Scaffold/fixtures/drupal-composer-drupal-project/composer.json.tmpl b/core/tests/Drupal/Tests/Composer/Plugin/Scaffold/fixtures/drupal-composer-drupal-project/composer.json.tmpl
index ae8877dcc2..83bd5ccea9 100644
--- a/core/tests/Drupal/Tests/Composer/Plugin/Scaffold/fixtures/drupal-composer-drupal-project/composer.json.tmpl
+++ b/core/tests/Drupal/Tests/Composer/Plugin/Scaffold/fixtures/drupal-composer-drupal-project/composer.json.tmpl
@@ -39,6 +39,11 @@
     "fixtures/drupal-core-fixture": "*",
     "fixtures/scaffold-override-fixture": "*"
   },
+  "config": {
+      "allow-plugins": {
+          "drupal/core-composer-scaffold": true
+      }
+  },
   "extra": {
     "drupal-scaffold": {
       "allowed-packages": [