diff --git a/core/modules/system/src/Tests/Lock/LockFunctionalTest.php b/core/modules/system/src/Tests/Lock/LockFunctionalTest.php
index 846b44d..cece86d 100644
--- a/core/modules/system/src/Tests/Lock/LockFunctionalTest.php
+++ b/core/modules/system/src/Tests/Lock/LockFunctionalTest.php
@@ -28,8 +28,8 @@ class LockFunctionalTest extends WebTestBase {
    */
   public function testLockAcquire() {
     $lock = $this->container->get('lock');
-    $lock_acquired = 'TRUE: Lock successfully acquired in system_test_lock_acquire()';
-    $lock_not_acquired = 'FALSE: Lock not acquired in system_test_lock_acquire()';
+    $lock_acquired = 'TRUE: Lock successfully acquired in \Drupal\system_test\Controller\SystemTestController::lockAcquire()';
+    $lock_not_acquired = 'FALSE: Lock not acquired in \Drupal\system_test\Controller\SystemTestController::lockAcquire()';
     $this->assertTrue($lock->acquire('system_test_lock_acquire'), 'Lock acquired by this request.', 'Lock');
     $this->assertTrue($lock->acquire('system_test_lock_acquire'), 'Lock extended by this request.', 'Lock');
     $lock->release('system_test_lock_acquire');
@@ -54,7 +54,7 @@ public function testLockAcquire() {
     $this->assertFalse($lock->acquire('system_test_lock_acquire'), 'Lock cannot be extended by this request.', 'Lock');
 
     // Check the shut-down function.
-    $lock_acquired_exit = 'TRUE: Lock successfully acquired in system_test_lock_exit()';
+    $lock_acquired_exit = 'TRUE: Lock successfully acquired in \Drupal\system_test\Controller\SystemTestController::lockExit()';
     $this->drupalGet('system-test/lock-exit');
     $this->assertText($lock_acquired_exit, 'Lock acquired by the other request before exit.', 'Lock');
     $this->assertTrue($lock->acquire('system_test_lock_exit'), 'Lock acquired by this request after the other request exits.', 'Lock');
diff --git a/core/modules/system/tests/modules/system_test/src/Controller/SystemTestController.php b/core/modules/system/tests/modules/system_test/src/Controller/SystemTestController.php
index 492f425..5544227 100644
--- a/core/modules/system/tests/modules/system_test/src/Controller/SystemTestController.php
+++ b/core/modules/system/tests/modules/system_test/src/Controller/SystemTestController.php
@@ -8,6 +8,7 @@
 namespace Drupal\system_test\Controller;
 
 use Drupal\Core\Controller\ControllerBase;
+use Symfony\Component\HttpFoundation\RedirectResponse;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 use Drupal\Core\Lock\LockBackendInterface;
@@ -76,17 +77,30 @@ public function drupalSetMessageTest() {
   }
 
   /**
-   * @todo Remove system_test_lock_acquire().
+   * Try to acquire a named lock and report the outcome.
    */
   public function lockAcquire() {
-    return system_test_lock_acquire();
+    if (\Drupal::lock()->acquire('system_test_lock_acquire')) {
+      \Drupal::lock()->release('system_test_lock_acquire');
+      return ['#markup' => 'TRUE: Lock successfully acquired in \Drupal\system_test\Controller\SystemTestController::lockAcquire()'];
+    }
+    else {
+      return ['#markup' => 'FALSE: Lock not acquired in \Drupal\system_test\Controller\SystemTestController::lockAcquire()'];
+    }
   }
 
   /**
-   * @todo Remove system_test_lock_exit().
+   * Try to acquire a specific lock, and then exit.
    */
   public function lockExit() {
-    return system_test_lock_exit();
+    if (\Drupal::lock()->acquire('system_test_lock_exit', 900)) {
+      echo 'TRUE: Lock successfully acquired in \Drupal\system_test\Controller\SystemTestController::lockExit()';
+      // The shut-down function should release the lock.
+      exit();
+    }
+    else {
+      return ['#markup' => 'FALSE: Lock not acquired in system_test_lock_exit()'];
+    }
   }
 
   /**
@@ -132,10 +146,14 @@ public static function preRenderCacheTags($elements) {
   }
 
   /**
-   * @todo Remove system_test_authorize_init_page().
+   * Initialize authorize.php during testing.
+   *
+   * @see system_authorized_init().
    */
   public function authorizeInit($page_title) {
-    return system_test_authorize_init_page($page_title);
+    $authorize_url = $GLOBALS['base_url'] . '/core/authorize.php';
+    system_authorized_init('system_test_authorize_run', drupal_get_path('module', 'system_test') . '/system_test.module', array(), $page_title);
+    return new RedirectResponse($authorize_url);
   }
 
   /**
@@ -151,10 +169,10 @@ public function setHeader(Request $request) {
   }
 
   /**
-   * @todo Remove system_test_page_shutdown_functions().
+   * A simple page callback which adds a register shutdown function.
    */
   public function shutdownFunctions($arg1, $arg2) {
-    system_test_page_shutdown_functions($arg1, $arg2);
+    drupal_register_shutdown_function('_system_test_first_shutdown_function', $arg1, $arg2);
     // If using PHP-FPM then fastcgi_finish_request() will have been fired
     // preventing further output to the browser which means that the escaping of
     // the exception message can not be tested.
diff --git a/core/modules/system/tests/modules/system_test/system_test.module b/core/modules/system/tests/modules/system_test/system_test.module
index b44e0a0..5e8a552 100644
--- a/core/modules/system/tests/modules/system_test/system_test.module
+++ b/core/modules/system/tests/modules/system_test/system_test.module
@@ -1,7 +1,6 @@
 <?php
 
 use Drupal\Core\Extension\Extension;
-use Symfony\Component\HttpFoundation\RedirectResponse;
 
 /**
  * Implements hook_modules_installed().
@@ -65,37 +64,6 @@ function system_test_system_info_alter(&$info, Extension $file, $type) {
 }
 
 /**
- * Try to acquire a named lock and report the outcome.
- *
- * @deprecated \Drupal\system_test\Controller\SystemTestController::lockAcquire()
- */
-function system_test_lock_acquire() {
-  if (\Drupal::lock()->acquire('system_test_lock_acquire')) {
-    \Drupal::lock()->release('system_test_lock_acquire');
-    return ['#markup' => 'TRUE: Lock successfully acquired in system_test_lock_acquire()'];
-  }
-  else {
-    return ['#markup' => 'FALSE: Lock not acquired in system_test_lock_acquire()'];
-  }
-}
-
-/**
- * Try to acquire a specific lock, and then exit.
- *
- * @deprecated \Drupal\system_test\Controller\SystemTestController::lockExit()
- */
-function system_test_lock_exit() {
-  if (\Drupal::lock()->acquire('system_test_lock_exit', 900)) {
-    echo 'TRUE: Lock successfully acquired in system_test_lock_exit()';
-    // The shut-down function should release the lock.
-    exit();
-  }
-  else {
-    return ['#markup' => 'FALSE: Lock not acquired in system_test_lock_exit()'];
-  }
-}
-
-/**
  * Implements hook_page_attachments().
  */
 function system_test_page_attachments(array &$page) {
@@ -107,15 +75,6 @@ function system_test_page_attachments(array &$page) {
 }
 
 /**
- * A simple page callback which adds a register shutdown function.
- *
- * @deprecated \Drupal\system_test\Controller\SystemTestController::shutdownFunctions()
- */
-function system_test_page_shutdown_functions($arg1, $arg2) {
-  drupal_register_shutdown_function('_system_test_first_shutdown_function', $arg1, $arg2);
-}
-
-/**
  * Dummy shutdown function which registers another shutdown function.
  */
 function _system_test_first_shutdown_function($arg1, $arg2) {
@@ -152,19 +111,6 @@ function system_test_filetransfer_info() {
 }
 
 /**
- * Page callback to initialize authorize.php during testing.
- *
- * @see system_authorized_init().
- *
- * @deprecated \Drupal\system_test\Controller\SystemTestController::authorizeInit()
- */
-function system_test_authorize_init_page($page_title) {
-  $authorize_url = $GLOBALS['base_url'] . '/core/authorize.php';
-  system_authorized_init('system_test_authorize_run', drupal_get_path('module', 'system_test') . '/system_test.module', array(), $page_title);
-  return new RedirectResponse($authorize_url);
-}
-
-/**
  * Implements hook_module_preinstall().
  */
 function system_test_module_preinstall($module) {