Issue #2850312 by heddn, Charlotte17, ohthehugemanatee, Gribnif, mikeryan,...

   * {@inheritdoc}

   */

  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration = NULL) {

    $migration_plugin_configuration = $configuration + [

      'migration' => 'd6_filter_format',

    ];

    return new static(

      $configuration,

      $plugin_id,

      $plugin_definition,

      $migration,

      $container->get('plugin.manager.migrate.process')->createInstance('migration', ['migration' => 'd6_filter_format'], $migration)

      $container->get('plugin.manager.migrate.process')->createInstance('migration', $migration_plugin_configuration, $migration)

    );

  }

<?php

namespace Drupal\Tests\filter\Kernel\Migrate\d6;

use Drupal\filter\Plugin\migrate\process\d6\FilterFormatPermission;

use Drupal\migrate\Plugin\Migration;

use Drupal\Tests\migrate_drupal\Kernel\MigrateDrupalTestBase;

/**

 * Tests conversion of format serial to string id in permission name.

 *

 * @coversDefaultClass \Drupal\filter\Plugin\migrate\process\d6\FilterFormatPermission

 *

 * @group filter

 */

class FilterFormatPermissionTest extends MigrateDrupalTestBase {

  /**

   * Tests configurability of filter_format migration name.

   *

   * @covers ::__construct

   */

  public function testConfigurableFilterFormat() {

    $migration = Migration::create($this->container, [], 'custom_migration', []);

    $filterFormatPermissionMigration = FilterFormatPermission::create($this->container, ['migration' => 'custom_filter_format'], 'custom_filter_format', [], $migration);

    $migrationPlugin = $this->readAttribute($filterFormatPermissionMigration, 'migrationPlugin');

    $config = $this->readAttribute($migrationPlugin, 'configuration');

    $this->assertEquals($config['migration'], 'custom_filter_format');

  }

}