Symfony\Component\Form\Exception\InvalidArgumentException: Could not load type "..."

this is my form:

<?php

namespace AppBundle\Form;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;

class JoseType extends AbstractType
{
    /**
     * @param FormBuilderInterface $builder
     * @param array $options
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('nombre')
            ->add('apellido')
            ->add('edad')
        ;
    }

    /**
     * @param OptionsResolverInterface $resolver
     */
    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => 'AppBundle\Entity\Jose'
        ));
    }

    /**
     * @return string
     */
    public function getName()
    {
        return 'appbundle_jose';
    }
}

And this is my test:

use AppBundle\Form\JoseType;
use Symfony\Component\Form\Test\TypeTestCase;

class ProjectTypeTest extends TypeTestCase
{
    public function testForm()
    {
         $form = $this->factory->create(JoseType::class);

    }
}

To running test receive this:

Symfony\Component\Form\Exception\InvalidArgumentException: Could not load type "AppBundle\Form\JoseType"

I have symfony 2.6.13.

In symfony 3.2 works, but 2.6 doesn't work, Why? ... any idea?