Network device configuration testing

Hi all, i've had a google but nothing came up so thought i'd pick your brians.

I've got a system where i'm generating network device configuration files using Ansible, .j2 templates and pulling the information from our DCIM(NexBox). The creation of the network device configs end up in a directory, simply saved as txt files and are not initially applied to the devices.

Is there any tool that you know of that is designed for testing the configuration files? or is there a good method for testing the network after the configs have been applied?

would be good to know what you all use.