inline lib/merge-modules.nix

it wasn't really adding value once I learned that evalModules
is at nixpkgs.lib

https://github.com/telent/liminix/compare/main...vesim987:liminix:main#diff-8ebcd005c04c8eddff72aa83f26a9ee6cfef3c04ce16b8f051aa6c6f4b0c9e73L1

tests/module/configuration.nix

@@ -1,10 +0,0 @@
-{ config, pkgs, ... } :
-{
-  imports = [ ./defs.nix ./module.nix ];
-  config = {
-    services.a.enable = true;
-    services.b.enable = true;
-
-    systemPackages = [ pkgs.hello ] ;
-  };
-}

tests/module/defs.nix

@@ -1,16 +0,0 @@
-{ lib, ...}:
-let inherit (lib) mkEnableOption mkOption types;
-in {
-  options = {
-    services.a = {
-      enable = mkEnableOption "hello service";
-    };
-    services.b = {
-      enable = mkEnableOption "other service";
-    };
-    services.z = mkOption {   };
-    systemPackages = mkOption {
-      type = types.listOf types.package;
-    };
-  };
-}

tests/module/module.nix

@@ -1,6 +0,0 @@
-{ config, pkgs, ... } :
-{
-  services.z = pkgs.figlet;
-
-  systemPackages = [ pkgs.units ] ;
-}

tests/module/run.sh

@@ -1,2 +0,0 @@
-set -e
-NIXPKGS_ALLOW_UNSUPPORTED_SYSTEM=1 nix-build --arg device "import <liminix/devices/qemu>" test.nix

tests/module/test.nix

@@ -1,17 +0,0 @@
-{ device }:
-let
-  overlay = import <liminix/overlay.nix> ;
-  nixpkgs = import <nixpkgs> ( device.system // {overlays = [overlay]; });
-  inherit (nixpkgs) lib pkgs;
-  inherit (lib.asserts) assertMsg;
-  config =
-    (import <liminix/merge-modules.nix>) [./configuration.nix] pkgs;
-  res1 = assertMsg
-    # check we have packages from both modules
-    (config.systemPackages == ( with pkgs; [ units hello ])) "failed";
-  res2 = let s = config.services;
-         in assertMsg (s.a.enable && s.b.enable && (s.z != null) ) "failed";
-in pkgs.writeText "foo" ''
-   ${if res1 then "OK" else "not OK"}
-   ${if res2 then "OK" else "not OK"}
-''