Index: branches/5.3.x/tools/class_locator.php
===================================================================
diff -u -r16395 -r16800
--- branches/5.3.x/tools/class_locator.php	(.../class_locator.php)	(revision 16395)
+++ branches/5.3.x/tools/class_locator.php	(.../class_locator.php)	(revision 16800)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: class_locator.php 16395 2016-11-12 12:43:14Z alex $
+* @version	$Id: class_locator.php 16800 2024-10-19 19:54:58Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2016 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -12,6 +12,8 @@
 * See http://www.in-portal.org/license for copyright notices and details.
 */
 
+use Composer\Autoload\ClassLoader;
+
 $start = microtime(true);
 
 define('DBG_ZEND_PRESENT', 1);
@@ -23,15 +25,37 @@
 $application = kApplication::Instance();
 $application->Init();
 
-/** @var \Composer\Autoload\ClassLoader $composer_class_loader */
+/** @var ClassLoader $composer_class_loader */
 $composer_class_loader = require FULL_PATH . '/vendor/autoload.php';
 
 return function ($class) use ($application, $composer_class_loader) {
+	// 1. Search for class within In-Portal.
 	$file = $application->findClassFile($class);
 
 	if ( $file !== false ) {
 		return $file;
 	}
 
-	return $composer_class_loader->findFile($class);
+	// 2. Search for class within Composer + register custom autoloaders.
+	$file = $composer_class_loader->findFile($class);
+
+	if ( $file !== false ) {
+		return $file;
+	}
+
+	// 3. Use custom autoloaders.
+	$dynamic_autoloader_namespaces = array(
+		'ConsoleHelpers\\PHPUnitCompat\\',
+		'Yoast\\PHPUnitPolyfills\\',
+	);
+
+	foreach ( $dynamic_autoloader_namespaces as $dynamic_autoloader_namespace ) {
+		if ( strpos($class, $dynamic_autoloader_namespace) !== 0 ) {
+			continue;
+		}
+
+		return (new ReflectionClass($class))->getFileName();
+	}
+
+	return false;
 };