Tek bir class alanı için assert validation constraint phpspec testi

namespace Application\BackendBundle\Validator\Constraint;

use Symfony\Component\Validator\Constraint;

/**
 * @Annotation
 */
class Username extends Constraint
{
    const INVALID_CONTENT = 'Username must form of only alphabetic and numeric characters.';

    public function validatedBy()
    {
        return get_class($this).'Validator';
    }
}

namespace Application\BackendBundle\Validator\Constraint;

use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;

class UsernameValidator extends ConstraintValidator
{
    public function validate($value, Constraint $constraint)
    {
        if (! ctype_alnum($value)) {
            $this->context
                ->buildViolation($constraint::INVALID_CONTENT)
                ->atPath('username')
                ->addViolation();
        }
    }
}

namespace spec\Application\BackendBundle\Validator\Constraint;

use PhpSpec\ObjectBehavior;
use Prophecy\Argument;
use Symfony\Component\Validator\Context\ExecutionContextInterface;
use Symfony\Component\Validator\Violation\ConstraintViolationBuilderInterface;
use Application\BackendBundle\Validator\Constraint\Username as Constraint;

class UsernameValidatorSpec extends ObjectBehavior
{
    function it_is_initializable()
    {
        $this->shouldHaveType('Application\BackendBundle\Validator\Constraint\UsernameValidator');
    }

    function it_should_not_validate_illegal_characters(
        ExecutionContextInterface $context,
        ConstraintViolationBuilderInterface $builder,
        Constraint $constraint
    ) {
        $this->initialize($context);

        $builder->addViolation()->shouldBeCalled();
        $builder->atPath('username')->willReturn($builder);

        $context->buildViolation(
            'Username must form of only alphabetic and numeric characters.'
        )->willReturn($builder);

        $this->validate('ab@£$123', $constraint);
    }

    function it_should_validate_legal_value(
        ExecutionContextInterface $context,
        ConstraintViolationBuilderInterface $builder,
        Constraint $constraint
    ) {
        $this->initialize($context);

        $builder->addViolation()->shouldNotBeCalled();

        $this->validate('inanzzz', $constraint);
    }
}