I have a home setup that right now is pretty straight forward. I have a DMZ, and host a VPN and some other things but it’s not SUPER complex. I am looking forward to adding more rules/VLANs, and subnetworks.

At work we employ TDD or test driven development, where we write the test that need to pass, and then code to that spec. Is there any way to do this with networking?

For example, I’d like a certain VLAN to allow access to network A, but not B. And perhaps one device uses a certain WAN gateway. There are many examples, but my goal is to kind of ensure that those rules aren’t broken as I continue to add more. Perhaps I should just write tests to verify and run them after any change? What are these tests typically written in? If that is the case how do I ensure the test “acts” as a different device (in testing it’s access)?

Maybe this isn’t even necessary if I understand better approaches? Any advice is appreciated.

I’m currently using OPNSense.