diff -u b/core/modules/config/src/Tests/ConfigSchemaTest.php b/core/modules/config/src/Tests/ConfigSchemaTest.php
--- b/core/modules/config/src/Tests/ConfigSchemaTest.php
+++ b/core/modules/config/src/Tests/ConfigSchemaTest.php
@@ -313,7 +313,7 @@
     // Finally update some object using a configuration wrapper.
     $new_slogan = 'Site slogan for testing configuration metadata';
     $wrapper = \Drupal::service('config.typed')->get('system.site');
-    \Drupal::config('system.site')->set('slogan', $new_slogan)->save();
+    \Drupal::configFactory()->getEditable('system.site')->set('slogan', $new_slogan)->save();
     $site_slogan = $wrapper->get('slogan');
     $this->assertEqual($site_slogan->getValue(), $new_slogan, 'Successfully updated the contained configuration data');
   }