tests\codeception\_support\AcceptanceTester Useless?

In yii2-basic template app, tests/codeception/_suppoprt/AcceptanceTester.php seems can define custom action.

class AcceptanceTester extends \Codeception\Actor


    use _generated\AcceptanceTesterActions;


    * Define custom actions here



     *  I tried to add a customer function


    public function foo() {




then in tests/codeception/acceptance/ContactCept.php, I try to use it

$I = new AcceptanceTester($scenario);

$I->wantTo('ensure that contact works');

$I->foo();   <=============================try to call this

$contactPage = ContactPage::openBy($I);

$I->see('Contact', 'h1');

$I->amGoingTo('submit contact form with no data');


Get exception

RuntimeException: Call to undefined method AcceptanceTester::foo


solved. yii2 does not read this file at all whatever junk I put into it, no process read it at all.