/**
 * @Route("/foobar")
 * @return Response
 */
public function fooAction()
{
    $form = $this->createForm(SomeFooType::class);

    $token = $this->get('security.csrf.token_manager')
        ->getToken('some_foo')
        ->getValue();

    $data = [
        'name'    => 'john',
        'surname' => 'doe',
        '_token'  => $token
    ];

    $form->submit($data);

    if ( $form->isSubmitted() ) {
        if ( $form->isValid() ) {
            return new Response("Form submitted and valid");
        }

        $errors = $form->getErrors(TRUE, TRUE);

        return new Response("Form submitted BUT not valid: " . (count($errors) ? $errors[0]->getMessage() : ""), 400);
    }

    return new Response("Form not submitted!");
}


class SomeFooType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('name', TextType::class, [
                'label'       => 'First name:',
                'constraints' => [
                    new NotBlank()
                ]
            ])
            ->add('surname', TextType::class, [
                'constraints' => [
                    new NotBlank()
                ]
            ]);
    }
}