edlp_d8/core/modules/comment/tests/modules/comment_test/comment_test.module

<?php

/**
 * @file
 * Dummy module implementing comment related hooks to test API interaction with
 * the Comment module.
 */

use Drupal\comment\CommentInterface;
use Drupal\Core\Url;

/**
 * Implements hook_entity_type_alter().
 */
function comment_test_entity_type_alter(array &$entity_types) {
  /** @var $entity_types \Drupal\Core\Entity\EntityTypeInterface[] */
  if (\Drupal::languageManager()->isMultilingual()) {
    // Enable language handling for comment fields.
    $translation = $entity_types['comment']->get('translation');
    $translation['comment_test'] = TRUE;
    $entity_types['comment']->set('translation', $translation);
  }
}

/**
 * Implements hook_comment_links_alter().
 */
function comment_test_comment_links_alter(array &$links, CommentInterface &$entity, array &$context) {
  // Allow tests to enable or disable this alter hook.
  if (!\Drupal::state()->get('comment_test_links_alter_enabled', FALSE)) {
    return;
  }

  $links['comment_test'] = [
    '#theme' => 'links__comment__comment_test',
    '#attributes' => ['class' => ['links', 'inline']],
    '#links' => [
      'comment-report' => [
        'title' => t('Report'),
        'url' => Url::fromRoute('comment_test.report', ['comment' => $entity->id()], ['query' => ['token' => \Drupal::getContainer()->get('csrf_token')->get("comment/{$entity->id()}/report")]]),
      ],
    ],
  ];
}