TestFieldConstraint.php

<?php

namespace Drupal\field_test\Plugin\Validation\Constraint;

use Drupal\Core\StringTranslation\TranslatableMarkup;
use Drupal\Core\Validation\Attribute\Constraint;
use Symfony\Component\Validator\Constraints\NotEqualTo;

/**
 * Checks if a value is not equal.
 */
class TestFieldConstraint extends NotEqualTo {
    
    /**
     * {@inheritdoc}
     */
    public function getRequiredOptions() : array {
        return [
            'value',
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function validatedBy() : string {
        return '\\Symfony\\Component\\Validator\\Constraints\\NotEqualToValidator';
    }

}