diff --git a/core/modules/system/lib/Drupal/system/Tests/Common/RenderElementTypesTest.php b/core/modules/system/lib/Drupal/system/Tests/Common/RenderElementTypesTest.php
index ed563a0..4b22a29 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Common/RenderElementTypesTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Common/RenderElementTypesTest.php
@@ -142,7 +142,7 @@ function testMaintenancePage() {
 
     // HTML element attributes.
     $html_attributes = new Attribute;
-    $language_interface = \Drupal::languageManager()->getLanguage(Language::TYPE_INTERFACE);
+    $language_interface = \Drupal::service('language_manager')->getCurrentLanguage();
     $html_attributes['lang'] = $language_interface->id;
     $html_attributes['dir'] = $language_interface->direction ? 'rtl' : 'ltr';
 
@@ -169,7 +169,7 @@ function testMaintenancePage() {
     drupal_add_html_head_link(array('rel' => 'shortcut icon', 'href' => Url::stripDangerousProtocols($favicon), 'type' => $type));
 
     // Build CSS links.
-    drupal_static_reset('drupal_add_css');
+    drupal_static_reset('_drupal_add_css');
     $path = drupal_get_path('module', 'system');
     $default_css = array(
       '#attached' => array(
@@ -182,7 +182,7 @@ function testMaintenancePage() {
       ),
     );
     drupal_render($default_css);
-    $css = drupal_add_css();
+    $css = _drupal_add_css();
 
     // Simulate the expected output of a "vanilla" maintenance page.
     $expected = <<<EOT
@@ -230,7 +230,7 @@ function testMaintenancePage() {
     );
 
     // We have to reset drupal_add_css between each test.
-    drupal_static_reset('drupal_add_css');
+    drupal_static_reset('_drupal_add_css');
 
     // Test basic string for maintenance page content.
     $elements = array(
@@ -248,7 +248,7 @@ function testMaintenancePage() {
     $this->assertElements($elements);
 
     // Test render array for maintenance page content.
-    drupal_static_reset('drupal_add_css');
+    drupal_static_reset('_drupal_add_css');
     $elements[0]['name'] = "#theme 'maintenance_page' with content as a render array";
     $elements[0]['value']['#content'] = array('#markup' => '<span>foo</span>');
     $this->assertElements($elements);