FOF30\Model\DataModel\Filter\Relation::callback PHP Метод

    public function callback($value)
    {
        return call_user_func($value, $this->subQuery);
    }

    /**
     * @group       RelationFilter
     * @group       RelationFilterCallback
     * @covers      FOF30\Model\DataModel\Filter\Relation::callback
     */
    public function testCallback()
    {
        $subquery = \JFactory::getDbo()->getQuery(true);
        $subquery->select('*')->from('test');
        $filter = new Relation(\JFactory::getDbo(), 'foo', $subquery);
        $result = $filter->callback(function ($query) {
            $query->where('bar = 1');
            return $query;
        });
        $check = 'SELECT *
FROM test
WHERE bar = 1';
        $this->assertEquals($check, trim((string) $result), 'Relation::callback Returned the wrong result');
    }