julienmonnerie/kirby/config/setup.php

<?php

/**
 * Class aliases
 */
$aliases = require_once __DIR__ . '/aliases.php';

spl_autoload_register(function ($class) use ($aliases) {
	$class = strtolower($class);

	if (isset($aliases[$class]) === true) {
		class_alias($aliases[$class], $class);
	}
});

/**
 * Tests
 */
$testDir = dirname(__DIR__) . '/tests';

if (is_dir($testDir) === true) {
	spl_autoload_register(function ($className) use ($testDir) {
		$path = str_replace('Kirby\\', '', $className);
		$path = str_replace('\\', '/', $path);
		$file = $testDir . '/' . $path . '.php';

		if (file_exists($file)) {
			include $file;
		}
	});
}