nixos/limine: add test for specialisations

nixos/tests/limine/default.nix

···
 {
   checksum = runTest ./checksum.nix;
   secureBoot = runTest ./secure-boot.nix;
+  specialisations = runTest ./specialisations.nix;
   uefi = runTest ./uefi.nix;
 }

nixos/tests/limine/specialisations.nix

···
+{ lib, ... }:
+{
+  name = "specialisations";
+  meta.maintainers = with lib.maintainers; [
+    lzcunt
+    phip1611
+    programmerlexi
+  ];
+  nodes.machine =
+    { ... }:
+    {
+      virtualisation.useBootLoader = true;
+      virtualisation.useEFIBoot = true;
+
+      specialisation.test = { };
+
+      boot.loader.efi.canTouchEfiVariables = true;
+      boot.loader.limine.enable = true;
+      boot.loader.limine.efiSupport = true;
+      boot.loader.timeout = 0;
+    };
+
+  testScript = ''
+    machine.start()
+    with subtest('Machine boots correctly'):
+      machine.wait_for_unit('multi-user.target')
+  '';
+}