anchor.diff:  
     machine = { lib, ... }: {
       imports = [ ./common/user-account.nix ];
  +    virtualisation.memorySize = 1024;
       services.xserver.enable = true;
       services.xserver.displayManager.sddm = {
         enable = true;
  
positive.code:         user = "alice";
        };
      };
      services.xserver.windowManager.default = "icewm";
      services.xserver.windowManager.icewm.enable = true;
      services.xserver.desktopManager.default = "none";
      services.xserver.desktopManager.kde5.enable = true;
    };
  
    enableOCR = true;
  
    testScript = { nodes, ... }: ''
      startAll;
      $machine->waitForFile("/home/alice/.Xauthority");
      $machine->succeed("xauth merge ~alice/.Xauthority");
      $machine->waitForWindow("^IceWM ");
    '';
  })
  
negative.code: import ./make-test.nix ({ pkgs, ...} :
  
  {
    name = "sddm";
    meta = with pkgs.stdenv.lib.maintainers; {
      maintainers = [ ttuegel ];
  