diff -u b/core/includes/bootstrap.inc b/core/includes/bootstrap.inc
--- b/core/includes/bootstrap.inc
+++ b/core/includes/bootstrap.inc
@@ -3560,7 +3560,7 @@
  *
  * @see Drupal\Component\PhpLoader\PhpLoaderInterface
  */
-function _drupal_php_get_loader($bin) {
+function drupal_php_loader($bin = 'default') {
   static $drupal_static_fast;
   if (!isset($drupal_static_fast)) {
     $drupal_static_fast['loader_objects'] = &drupal_static(__FUNCTION__);
@@ -3583,38 +3582,0 @@
-
-/**
- * include a PHP file.
- *
- * @param string $filename
- *   The filename. Can be a relative path.
- * @param string $bin
- *   An optional bin. Separate bins can use a different loader class.
- */
-function drupal_php_include($filename, $bin = 'default') {
-  return _drupal_php_get_loader($bin)->phpInclude($filename);
-}
-
-/**
- * Write a PHP file.
- *
- * @param string $filename
- *   The filename. Can be a relative path.
- * @param string $data
- *   The PHP code to be written.
- * @param string $bin
- *   An optional bin. Separate bins can use a different loader class.
- */
-function drupal_php_write($filename, $data, $bin = 'default') {
-  return _drupal_php_get_loader($bin)->write($filename, $data);
-}
-
-/**
- * Delete a PHP file.
- *
- * @param string $filename
- *   The filename to be deleted. Can be a relative path.
- * @param string $bin
- *   An optional bin. Separate bins can use a different loader class.
- */
-function drupal_php_delete($filename, $bin = 'default') {
-  return _drupal_php_get_loader($bin)->delete($filename);
-}
diff -u b/core/lib/Drupal/Component/PhpLoader/MTimeProtectedLoader.php b/core/lib/Drupal/Component/PhpLoader/MTimeProtectedLoader.php
--- b/core/lib/Drupal/Component/PhpLoader/MTimeProtectedLoader.php
+++ b/core/lib/Drupal/Component/PhpLoader/MTimeProtectedLoader.php
@@ -32,9 +32,9 @@
   }
 
   /**
-   * Implements Drupal\Component\PhpLoader\PhpLoaderInterface::phpInclude()
+   * Implements Drupal\Component\PhpLoader\PhpLoaderInterface::includePhp()
    */
-  public function phpInclude($filename) {
+  public function includePhp($filename) {
     $filename = str_replace('/', '#', $filename);
     $dir = $this->prefix . '/' . $filename;
     $filename = $this->getPath($dir, $filename, filemtime($dir));
diff -u b/core/lib/Drupal/Component/PhpLoader/NativeLoader.php b/core/lib/Drupal/Component/PhpLoader/NativeLoader.php
--- b/core/lib/Drupal/Component/PhpLoader/NativeLoader.php
+++ b/core/lib/Drupal/Component/PhpLoader/NativeLoader.php
@@ -27,7 +27,7 @@
   /**
    * Implements Drupal\Component\PhpLoader\PhpLoaderInterface::include()
    */
-  public function phpInclude($filename) {
+  public function includePhp($filename) {
     include_once $this->prefix . '/' . $filename;
     return TRUE;
   }
diff -u b/core/lib/Drupal/Component/PhpLoader/PhpLoaderInterface.php b/core/lib/Drupal/Component/PhpLoader/PhpLoaderInterface.php
--- b/core/lib/Drupal/Component/PhpLoader/PhpLoaderInterface.php
+++ b/core/lib/Drupal/Component/PhpLoader/PhpLoaderInterface.php
@@ -12,7 +12,7 @@
    * @return
    *   TRUE if the include was successful.
    */
-  public function phpInclude($filename);
+  public function includePhp($filename);
 
   /**
    * Write a PHP file.
diff -u b/core/modules/simpletest/simpletest.module b/core/modules/simpletest/simpletest.module
--- b/core/modules/simpletest/simpletest.module
+++ b/core/modules/simpletest/simpletest.module
@@ -528,8 +528,8 @@
  *   The path that will be obliterated.
  */
 function _simpletest_delete_recursive($path) {
-  // We can not use file_unmanaged_delete_recursive because it
-  // deliberately only removes visible files with write permission.
+  // file_unmanaged_delete_recursive()  deliberately only removes visible
+  // files with write permission.
   chmod($path, 0700);
   file_unmanaged_delete_recursive($path, '_simpletest_delete_recursive');
 }
diff -u b/core/modules/system/lib/Drupal/system/Tests/PhpLoader/MTimeProtectedLoaderTest.php b/core/modules/system/lib/Drupal/system/Tests/PhpLoader/MTimeProtectedLoaderTest.php
--- b/core/modules/system/lib/Drupal/system/Tests/PhpLoader/MTimeProtectedLoaderTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/PhpLoader/MTimeProtectedLoaderTest.php
@@ -7,9 +7,9 @@
 
 namespace Drupal\system\Tests\PhpLoader;
 
-use Drupal\simpletest\WebTestBase;
+use Drupal\simpletest\UnitTestBase;
 
-class MTimeProtectedLoaderTest extends WebTestBase {
+class MTimeProtectedLoaderTest extends UnitTestBase {
 
   public static function getInfo() {
     return array(
@@ -20,13 +20,13 @@
   }
 
   public function testMTimeProtectedLoader() {
-    variable_set('loader_classes', array('default' =>
+    $conf['loader_classes'] = array('default' =>
       array(
         'class' => 'Drupal\Component\PhpLoader\MTimeProtectedLoader',
         'prefix' => variable_get('file_public_path', conf_path() . '/files') . '/codegen',
         'secret' => $GLOBALS['drupal_hash_salt'],
       ),
-    ));
+    );
     drupal_static_reset('_drupal_php_get_loader');
     $filename = $this->randomName() . '/' . $this->randomName() . '.php';
     do {
@@ -34,8 +34,8 @@
       $function = 'test' . $random;
     } while (function_exists($function));
     $contents = "<?php\nfunction $function() { return $random;}";
-    drupal_php_write($filename, $contents);
-    drupal_php_include($filename);
+    drupal_php_loader()->write($filename, $contents);
+    drupal_php_loader()->includePhp($filename);
     $this->assertIdentical($function(), $random);
   }
 }