diff --git a/core/modules/system/tests/modules/form_test/form_test.module b/core/modules/system/tests/modules/form_test/form_test.module
index 3e7c089..afc25fc 100644
--- a/core/modules/system/tests/modules/form_test/form_test.module
+++ b/core/modules/system/tests/modules/form_test/form_test.module
@@ -288,12 +288,6 @@ function form_test_menu() {
       'type' => MENU_CALLBACK,
     );
   }
-  $items['form-test/double-form'] = array(
-    'title' => 'Double form test',
-    'page callback' => 'form_test_double_form',
-    'access callback' => TRUE,
-    'type' => MENU_CALLBACK,
-  );
 
   $items['form-test/load-include-menu'] = array(
     'title' => 'FAPI test loading includes',
@@ -2351,32 +2345,6 @@ function form_test_required_attribute($form, &$form_state) {
 }
 
 /**
- * Menu callback returns two instances of the same form.
- */
-function form_test_double_form() {
-  return array(
-    'form1' => drupal_get_form('form_test_html_id'),
-    'form2' => drupal_get_form('form_test_html_id'),
-  );
-}
-
-/**
- * Builds a simple form to test duplicate HTML IDs.
- */
-function form_test_html_id($form, &$form_state) {
-  $form['name'] = array(
-    '#type' => 'textfield',
-    '#title' => 'name',
-    '#required' => TRUE,
-  );
-  $form['submit'] = array(
-    '#type' => 'submit',
-    '#value' => 'Save',
-  );
-  return $form;
-}
-
-/**
  * Builds a simple form to test form button classes.
  */
 function form_test_button_class($form, &$form_state) {
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 34e437d..f086bd2 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
@@ -67,3 +67,11 @@ form_test.autocomplete_2:
     controller: '\Drupal\form_test\AutocompleteController::autocomplete1'
   requirements:
     _permission: 'access autocomplete test'
+
+form_test.route9:
+  title: 'Double form test'
+  pattern: '/form-test/double-form'
+  defaults:
+    _form: '\Drupal\form_test\FormTestDoubleForm'
+  requirements:
+    _access: 'TRUE'
diff --git a/core/modules/system/tests/modules/form_test/lib/Drupal/form_test/FormTestDoubleForm.php b/core/modules/system/tests/modules/form_test/lib/Drupal/form_test/FormTestDoubleForm.php
new file mode 100644
index 0000000..8ab8c42
--- /dev/null
+++ b/core/modules/system/tests/modules/form_test/lib/Drupal/form_test/FormTestDoubleForm.php
@@ -0,0 +1,39 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\form_test\FormTestDoubleForm.
+ */
+
+namespace Drupal\form_test;
+
+use Drupal\Core\Form\FormInterface;
+
+/**
+ * Provides a simple form to test duplicate HTML IDs.
+ */
+class FormTestDoubleForm implements FormInterFace {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormID() {
+    return 'form_test_double_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, array &$form_state) {
+    $form['name'] = array(
+      '#type' => 'textfield',
+      '#title' => 'name',
+      '#required' => TRUE,
+    );
+    $form['submit'] = array(
+      '#type' => 'submit',
+      '#value' => 'Save',
+    );
+    return $form;
+  }
+}