Creating external entity types in KernelTests no longer works

Problem/Motivation

Hello,

our tests started to fail after updating to 3.0.0-beta6 and I believe it is caused by changes in https://www.drupal.org/project/external_entities/issues/3056530 → .

We are importing external_entity config in our tests, which triggers route rebuilding. This then triggers the event which calls getAllRoutes(). In KernelTests, RouteProviderInterface is implemented by RouteProvider, which calls route rebuilding again. This triggers an exception, since route rebuilding is already in progress.

Steps to reproduce

I created this test that passes in 3.0.0-beta5, but fails in 3.0.0-beta6.

<?php

declare(strict_types=1);

namespace Drupal\Tests\external_entities\Kernel;

use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\external_entities\Entity\ExternalEntityType;
use Drupal\KernelTests\KernelTestBase;

/**
 * Test importing config from external_entities_drupalorg.
 *
 * @group ExternalEntities
 */
class DrupalOrgExternalEntityTest extends KernelTestBase {

  /**
   * {@inheritdoc}
   */
  protected static $modules = [
    'external_entities',
    'external_entities_drupalorg',
  ];

  /**
   * {@inheritdoc}
   */
  protected $strictConfigSchema = FALSE;

  /**
   * Test config import.
   */
  public function testExternalEntityType(): void {
    $this->installEntitySchema('external_entity_type');
    $this->installConfig(['external_entities_drupalorg']);

    $entityType = $this->container
      ->get(EntityTypeManagerInterface::class)
      ->getStorage('external_entity_type')
      ->load('drupalorg_jsonapi_module');

    $this->assertInstanceOf(ExternalEntityType::class, $entityType);
  }

}

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes