navigation_test.module

<?php


/**
 * @file
 * Contains main module functions.
 */
declare (strict_types=1);
use Drupal\Component\Utility\Html;

/**
 * Implements hook_preprocess_HOOK().
 */
function navigation_test_preprocess_block__navigation(&$variables) {
    // Add some additional classes so we can target the correct contextual link
    // in tests.
    $variables['attributes']['class'][] = Html::cleanCssIdentifier('block-' . $variables['elements']['#plugin_id']);
}