class RestTestHooks

class RestTestHooks {
  
  /**
   * Implements hook_entity_field_access().
   *
   * @see \Drupal\Tests\rest\Functional\EntityResource\EntityResourceTestBase::setUp()
   */
  public function entityFieldAccess($operation, FieldDefinitionInterface $field_definition, AccountInterface $account, ?FieldItemListInterface $items = NULL) : AccessResultInterface {
    // @see \Drupal\Tests\rest\Functional\EntityResource\EntityResourceTestBase::testPost()
    // @see \Drupal\Tests\rest\Functional\EntityResource\EntityResourceTestBase::testPatch()
    if ($field_definition->getName() === 'field_rest_test') {
      switch ($operation) {
        case 'view':
          // Never ever allow this field to be viewed: this lets
          // EntityResourceTestBase::testGet() test in a "vanilla" way.
          return AccessResult::forbidden();
        case 'edit':
          return AccessResult::forbidden();
      }
    }
    // @see \Drupal\Tests\rest\Functional\EntityResource\EntityResourceTestBase::testGet()
    // @see \Drupal\Tests\rest\Functional\EntityResource\EntityResourceTestBase::testPatch()
    if ($field_definition->getName() === 'field_rest_test_multivalue') {
      switch ($operation) {
        case 'view':
          // Never ever allow this field to be viewed: this lets
          // EntityResourceTestBase::testGet() test in a "vanilla" way.
          return AccessResult::forbidden();
      }
    }
    // @see \Drupal\Tests\rest\Functional\EntityResource\EntityResourceTestBase::testGet()
    // @see \Drupal\Tests\rest\Functional\EntityResource\EntityResourceTestBase::testPatch()
    if ($field_definition->getName() === 'rest_test_validation') {
      switch ($operation) {
        case 'view':
          // Never ever allow this field to be viewed: this lets
          // EntityResourceTestBase::testGet() test in a "vanilla" way.
          return AccessResult::forbidden();
      }
    }
    // No opinion.
    return AccessResult::neutral();
  }
  
  /**
   * Implements hook_entity_base_field_info().
   */
  public function entityBaseFieldInfo(EntityTypeInterface $entity_type) : array {
    $fields = [];
    $fields['rest_test_validation'] = BaseFieldDefinition::create('string')->setLabel('REST test validation field')
      ->setDescription('A text field with some special validations attached used for testing purposes')
      ->addConstraint('rest_test_validation');
    return $fields;
  }

}