diff --git a/core/modules/system/tests/modules/test_page_test/src/Controller/TestPageTestController.php b/core/modules/system/tests/modules/test_page_test/src/Controller/TestPageTestController.php
index 76ac189..ca423c8 100644
--- a/core/modules/system/tests/modules/test_page_test/src/Controller/TestPageTestController.php
+++ b/core/modules/system/tests/modules/test_page_test/src/Controller/TestPageTestController.php
@@ -13,10 +13,18 @@
 class TestPageTestController {
 
   /**
-   * @todo Remove test_page_test_page().
+   * Returns a test page and sets the title.
    */
   public function testPage() {
-    return test_page_test_page();
+    return [
+      '#title' => t('Test page'),
+      '#markup' => t('Test page text.'),
+      '#attached' => [
+        'drupalSettings' => [
+          'test-setting' => 'azAZ09();.,\\\/-_{}',
+        ],
+      ],
+    ];
   }
 
 }
diff --git a/core/modules/system/tests/modules/test_page_test/test_page_test.module b/core/modules/system/tests/modules/test_page_test/test_page_test.module
deleted file mode 100644
index f2967cf..0000000
--- a/core/modules/system/tests/modules/test_page_test/test_page_test.module
+++ /dev/null
@@ -1,15 +0,0 @@
-<?php
-
-/**
- * Page callback: Returns a test page and sets the title.
- *
- * @deprecated Use \Drupal\test_page_test\Controller\TestPageTestController::testPage()
- */
-function test_page_test_page() {
-  $attached['drupalSettings']['test-setting'] = 'azAZ09();.,\\\/-_{}';
-  return array(
-    '#title' => t('Test page'),
-    '#markup' => t('Test page text.'),
-    '#attached' => $attached,
-  );
-}