smarty-lint was developed out of necessity and with simplicity of use in mind. Many of us all have committed broken templates file into our VCS without proper testing only to have it break a page because of a missing $, or that you forgot to close out your {foreach} statement.
From here you can easily integrate smarty-lint into your build system, so that before committing anything into your source tree you can run template lint checks alongside your normal code lints.
Install via composer:
composer require developerdino/smarty-lint --dev