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

<?php

/**
 * @file
 * Provides configuration entity static cache test helpers.
 */

use Drupal\Component\Utility\Random;

/**
 * Implements hook_ENTITY_TYPE_load() for 'static_cache_test_config_test'.
 */
function config_entity_static_cache_test_config_test_load($entities) {
  static $random;
  if (!$random) {
    $random = new Random();
  }
  foreach ($entities as $entity) {
    // Add a random stamp for every load(), so that during tests, we can tell
    // if an entity was retrieved from cache (unchanged stamp) or reloaded.
    $entity->_loadStamp = $random->string(8, TRUE);
  }
}

/**
 * Implements hook_entity_type_alter().
 */
function config_entity_static_cache_test_entity_type_alter(array &$entity_types) {
  /** @var $entity_types \Drupal\Core\Entity\EntityTypeInterface[] */
  $entity_types['config_test']->set('static_cache', TRUE);
}