Form provides tools for defining forms, rendering and mapping request data to related models. Furthermore it provides integration with the Validation component.
Silex integration:
https://github.com/fabpot/Silex/blob/master/src/Silex/Provider/FormServiceProvider.php
Documentation:
http://symfony.com/doc/2.5/book/forms.html
You can run the unit tests with the following command:
$ cd path/to/Symfony/Component/Form/
$ composer.phar install
$ phpunit