Codeception - What is the difference between cest and cept?

Their format is the only difference.

Cept is a scenario-based format and Cest is a class based format.

Cept example:

<?php    $I = new AcceptanceTester($scenario);$I->wantTo('log in as regular user');$I->amOnPage('/login');$I->fillField('Username','john');$I->fillField('Password','secret');$I->click('Login');$I->see('Hello john');

Cest example:

<?phpclass UserCest{    public function loginAsRegularUser(\AcceptanceTester $I)     {        $I->wantTo('log in as regular user');        $I->amOnPage('/login');        $I->fillField('Username','john');        $I->fillField('Password','secret');        $I->click('Login');        $I->see('Hello john');                }}

Non-developers may find the Cept format more friendly and approachable. PHP developers may prefer the Cest format which is able to support multiple tests per file and easy reuse of code by adding additional private functions.

In the end it is just a matter of taste and you can choose the format you prefer.

If you have a Cest with 2 test methods like

<?phpclass UserCest{    public function test1(\AcceptanceTester $I)     {        $I->see('Hello john');                }    public function test2(\AcceptanceTester $I)     {        $I->see('Hello jeff');                }}

That is thew Equivalent totest1Cept.php:

<?php$I = new AcceptanceTester($scenario);$I->see('Hello john');

test2Cept.php:

<?php$I = new AcceptanceTester($scenario);$I->see('Hello jeff');

It's just 2 different ways of structuring you test code

Not that I'm a Codeception expert but this description may help - http://codeception.com/docs/07-AdvancedUsage.