edlp_d8/core/modules/config/tests/config_test/config_test.module

<?php

/**
 * @file
 * Provides Config module hook implementations for testing purposes.
 */

require_once dirname(__FILE__) . '/config_test.hooks.inc';

/**
 * Implements hook_cache_flush().
 */
function config_test_cache_flush() {
  // Set a global value we can check in test code.
  $GLOBALS['hook_cache_flush'] = __FUNCTION__;
}

/**
 * Implements hook_entity_type_alter().
 */
function config_test_entity_type_alter(array &$entity_types) {
  /** @var $entity_types \Drupal\Core\Entity\EntityTypeInterface[] */
  // The 'translatable' entity key is not supposed to change over time. In this
  // case we can safely do it because we set it once and we do not change it for
  // all the duration of the test session.
  $entity_types['config_test']->set('translatable', \Drupal::service('state')->get('config_test.translatable'));

  // Create a clone of config_test that does not have a status.
  $entity_types['config_test_no_status'] = clone $entity_types['config_test'];
  $config_test_no_status = &$entity_types['config_test_no_status'];
  $config_test_no_status->setLinkTemplate('edit-form', '/admin/structure/config_test/manage/{config_test_no_status}');
  $config_test_no_status->setLinkTemplate('delete-form', '/admin/structure/config_test/manage/{config_test_no_status}/delete');

  $keys = $config_test_no_status->getKeys();
  unset($keys['status']);
  $config_test_no_status->set('id', 'config_test_no_status');
  $config_test_no_status->set('entity_keys', $keys);
  $config_test_no_status->set('config_prefix', 'no_status');
  if (\Drupal::service('state')->get('config_test.lookup_keys', FALSE)) {
    $entity_types['config_test']->set('lookup_keys', ['uuid', 'style']);
  }
}