How would I easily test a flake's default module?

I’m trying to make a Nix flake that has a configurable default module. I frequently have to run nix flake update from my system’s flake and then run home-manager switch --flake .. This takes up a lot of requests in several places and I soon become unable to test my output in that method.

I also can use nix-repl and load the flake and just import the default.nix file, but that seems, to put it bluntly, smelly.

Should I create a test system configuration in my flake and use that? I’ve read of dev-shells and things like that but it doesn’t seem like that’s the “bona fide” way of testing. I also tried looking into nixt but that’s just… horribly broken.

I’m doing it via the NixOS test framework, feel free to steal the necessary bits of code GitHub - wamserma/flake-programs-sqlite: A simple flake to automagically specify programs.sqlite for command-not-found.