NixOS module test skeleton

module.nix

{ config, lib, ... }:

with lib;

let
  cfg = config.foo.bar;
  
in

{
  options.foo.bar = {
    enable = mkEnableOption "foobar";
  };
  
  config = mkIf cfg.enable {
    # ...
  };
}

tests.nix

{ system ? builtins.currentSystem
, pkgs ? import <nixpkgs> { inherit system; }
}:

with import <nixpkgs/nixos/lib/testing-python.nix> { inherit system pkgs; };

{
  mytest = makeTest {
    machine = { ... }: {
      imports = [ ./module.nix ];
      
      virtualisation.cores = 4;
      virtualisation.memorySize = 1024;
      
      foo.bar.enable = true;
    };
    
    testScript = ''
      machine.start()
    '';
  };
}