Regula-nix

{
regula.rules = {
    sshdMustBeEnabled = {
        enable = true;
        eval.assertion.is = config.services.openssh.enable;
        build = {
            toplevel = {testData, failureContext}:{}; #a script that must return true when run against nixos output
            perPackage = {testData, failureContext }:{}; # derivation that must build successfully.
        };
        vm = {
            # This uses pytest with intergrations to the boot lifecycle of the system.
            testScript = ''
                with subtest("sshd must be enabled"):
                    machine.wait_for_unit("sshd.service")
                    machine.succeed("systemctl is-active -q sshd.service")
            '';
        };
        # extra info and data about this test that is available when relevant.
        meta = {
            # failureContext becomes a multiline string that is useful
            failureContext = {
                name = "openssh is not enabled";
            };
            # testData is available un alterd for use in relevant functions.
            testData = {
                example = "foo";
            };
        };
    };
};
}