--- /dev/null
+<?php
+
+namespace Drupal\config_test;
+
+use Drupal\Core\Config\ConfigFactoryInterface;
+use Drupal\Core\Config\Schema\SchemaIncompleteException;
+use Drupal\Core\Controller\ControllerBase;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Controller for testing \Drupal\Core\Config\Development\ConfigSchemaChecker.
+ */
+class SchemaListenerController extends ControllerBase {
+
+ /**
+ * Constructs the SchemaListenerController object.
+ *
+ * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
+ * The config factory.
+ */
+ public function __construct(ConfigFactoryInterface $config_factory) {
+ $this->configFactory = $config_factory;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public static function create(ContainerInterface $container) {
+ return new static(
+ $container->get('config.factory')
+ );
+ }
+
+ /**
+ * Tests the WebTestBase tests can use strict schema checking.
+ */
+ public function test() {
+ try {
+ $this->configFactory->getEditable('config_schema_test.schemaless')->set('foo', 'bar')->save();
+ }
+ catch (SchemaIncompleteException $e) {
+ return [
+ '#markup' => $e->getMessage(),
+ ];
+ }
+ }
+
+}