public final static function drop_parallel_site_links() {
        global $CFG;

        // Get parallel test runs.
        $parallelrun = self::get_behat_run_config_value('parallel');

        if (empty($parallelrun)) {
            return false;
        }

        // If parallel run then remove links and original file.
        clearstatcache();
        for ($i = 1; $i <= $parallelrun; $i++) {
            // Don't delete links for specified sites, as they should be accessible.
            if (!empty($CFG->behat_parallel_run['behat_wwwroot'][$i - 1]['behat_wwwroot'])) {
                continue;
            }
            $link = $CFG->dirroot . '/' . BEHAT_PARALLEL_SITE_NAME . $i;
            if (file_exists($link) && is_link($link)) {
                @unlink($link);
            }
        }
        return true;
    }