yii2-app-basic/tests/codeception/acceptance/ContactCest.php

<?php

/**
 * Class ContactCest
 */
class ContactCest
{
    public function _before(\AcceptanceTester $I)
    {
        $I->amOnPage('index-test.php?r=site%2Fcontact');
    }
    
    public function contactPageWorks(AcceptanceTester $I)
    {
        $I->wantTo('ensure that contact page works');
        $I->see('Contact', 'h1');
    }

    public function contactFormCanBeSubmitted(AcceptanceTester $I)
    {
        $I->amGoingTo('submit contact form with correct data');
        $I->fillField('#contactform-name', 'tester');
        $I->fillField('#contactform-email', 'tester@example.com');
        $I->fillField('#contactform-subject', 'test subject');
        $I->fillField('#contactform-body', 'test content');
        $I->fillField('#contactform-verifycode', 'testme');

        $I->click('contact-button');

        $I->dontSeeElement('#contact-form');
        $I->see('Thank you for contacting us. We will respond to you as soon as possible.');
    }
}