class TestType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('choice', 'choice', ['choices' => ['foo', 'bar']]);
    }

    public function getName()
    {
        return 'test';
    }
}

class DefaultController extends Controller
{
    public function indexAction(Request $request)
    {
        return $this->render('AppBundle::index.html.php', [
            'form' => $this->createForm('test')->createView(),
        ]);
    }
}

<?php echo $view['form']->widget($form['choice']) ?>