szurubooru/tests/ConfigMock.php

<?php
namespace Szurubooru\Tests;
use Szurubooru\Config;

final class ConfigMock extends Config
{
    public function set($key, $value)
    {
        $keys = preg_split('/[\\/]/', $key);
        $current = $this;
        $lastKey = array_pop($keys);
        foreach ($keys as $key)
        {
            if (!isset($current->$key))
                $current->$key = new \ArrayObject([], \ArrayObject::ARRAY_AS_PROPS);
            $current = $current->$key;
        }
        $current->$lastKey = $value;
    }
}