wordpress: login to user "avni_temp_user" and then log out

function wordpress_login_and_logout() {
    $I = $this;

    $I->amOnPage('/wp-login.php');
    $I->fillField('#user_login', 'avni_temp_user');
    $I->fillField('#user_pass', '123456');
    $I->click('#wp-submit');

    //log out
    $I->click('a.ab-item');
}