constants not working v3.1.23 about smarty HOT 3 CLOSED

<?php

require __DIR__ . '/smarty-3.1.23/libs/Smarty.class.php';

// !!!
//define('TEST_CONST', false);

class Template extends Smarty
{
    public function __construct()
    {
        parent::__construct();

        $this->setTemplateDir(__DIR__ . '/templates/')
            ->setCompileDir(__DIR__ . '/templates_c/')
            ->setConfigDir(__DIR__ . '/configs/')
            ->setCacheDir(__DIR__ . '/cache/');

        $this->compile_check = true;
        //$this->default_modifiers = array('escape:"htmlall"');
    }

}


$obj = new Template();
$obj->display('test.tpl');