EntityTestCompositeConstraintValidator.php

<?php

namespace Drupal\entity_test\Plugin\Validation\Constraint;

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

/**
 * Constraint validator for the EntityTestComposite constraint.
 */
class EntityTestCompositeConstraintValidator extends ConstraintValidator {
  
  /**
   * {@inheritdoc}
   */
  public function validate($entity, Constraint $constraint) {
    if ($entity->name->value === 'test' && $entity->type->value === 'test2') {
      $this->context
        ->buildViolation($constraint->message)
        ->atPath('type')
        ->addViolation();
    }
    if ($entity->name->value === 'failure-field-name') {
      $this->context
        ->buildViolation('Name field violation')
        ->atPath('name')
        ->addViolation();
    }
    elseif ($entity->name->value === 'failure-field-type') {
      $this->context
        ->buildViolation('Type field violation')
        ->atPath('type')
        ->addViolation();
    }
  }

}