user_hooks_test.module

<?php


/**
 * @file
 * Support module for user hooks testing.
 */
use Drupal\Component\Render\FormattableMarkup;
use Drupal\Core\Session\AccountInterface;

/**
 * Implements hook_user_format_name_alter().
 */
function user_hooks_test_user_format_name_alter(&$name, AccountInterface $account) {
    if (\Drupal::state()->get('user_hooks_test_user_format_name_alter', FALSE)) {
        if (\Drupal::state()->get('user_hooks_test_user_format_name_alter_safe', FALSE)) {
            $name = new FormattableMarkup('<em>@uid</em>', [
                '@uid' => $account->id(),
            ]);
        }
        else {
            $name = '<em>' . $account->id() . '</em>';
        }
    }
}