public static function drop_dataroot() {
        global $CFG;

        // As behat directory is now created under default $CFG->behat_dataroot_parent, so remove the whole dir.
        if ($CFG->behat_dataroot !== $CFG->behat_dataroot_parent) {
            remove_dir($CFG->behat_dataroot, false);
        } else {
            // It should never come here.
            throw new moodle_exception("Behat dataroot should not be same as parent behat data root.");
        }
    }