PHPUnits custom assertions using Symfony Validator

CustomTestCase.php

<?php
/**
 * Created by Baudev
 * http://github.com/baudev
 * Date: 08/03/2019
 */

namespace App\Tests\Helper; // according to your project


use PHPUnit\Framework\TestCase;
use Symfony\Component\Validator\Validator\ValidatorInterface;

/**
 * Decorated TestCase class.
 *
 * @package App\Tests\Helper
 * @author Baudev
 * @since 1.0
 * @link https://phpunit.readthedocs.io/en/8.0/extending-phpunit.html
 */
abstract class CustomTestCase extends TestCase {

    /**
     * Adds the assertion using Symfony Validator.
     *
     * @param $condition
     * @param string $message
     * @see ValidatorInterface
     */
    public static function assertSymfonyValidate($condition, $message = ''){
        self::assertThat($condition, self::isSymfonyValidate(), $message);
    }

    /**
     * Returns the evaluation class.
     *
     * @return IsSymfonyValidate
     * @see IsSymfonyValidate::matches()
     */
    public static function isSymfonyValidate() {
        return new IsSymfonyValidate;
    }

}

IsSymfonyValidate.php

<?php
/**
 * Created by Baudev
 * http://github.com/baudev
 * Date: 08/03/2019
 */

namespace App\Tests\Helper; // according to your project


use PHPUnit\Framework\Constraint\Constraint;
use Symfony\Component\Validator\Validation;

/**
 * Evaluation class using the Symfony Validator.
 *
 * @package App\Tests\Helper
 * @author Baudev
 * @since 1.0
 * @link https://symfony.com/doc/current/validation.html
 */
class IsSymfonyValidate extends Constraint
{

    /**
     * @var \Symfony\Component\Validator\Validator\RecursiveValidator|\Symfony\Component\Validator\Validator\ValidatorInterface
     */
    private $validator;

    /**
     * IsSymfonyValidate constructor.
     */
    public function __construct()
    {
        parent::__construct();
        $this->validator = Validation::createValidatorBuilder()->enableAnnotationMapping()->getValidator();
    }

    /**
     * Evaluates if the object $other is validated by the Symfony Normalizer.
     *
     * @param mixed $other
     * @return bool
     */
    protected function matches($other)
    {
        return $this->validator->validate($other)->count() === 0;
    }

    /**
     * Returns a string representation of the object.
     *
     * @return string
     */
    public function toString()
    {
        return 'is validated';
    }
}

Tested with Symfony 4.2, PHPUnits 8.0, PHP 7.2.15.