anchor.diff:  
     machine = { lib, ... }: {
       imports = [ ./common/user-account.nix ];
  +    virtualisation.memorySize = 1024;
       services.xserver.enable = true;
       services.xserver.displayManager.sddm = {
         enable = true;
  
positive.code: import ./make-test.nix ({ pkgs, ...} : {
    name = "sddm";
    meta = with pkgs.stdenv.lib.maintainers; {
      maintainers = [ ttuegel ];
  
negative.code:         user = "alice";
        };
      };
      services.xserver.desktopManager.kde5.enable = true;
    };
  
    enableOCR = true;
  
    testScript = { nodes, ... }:
    let xdo = "${pkgs.xdotool}/bin/xdotool"; in
     ''     
      sub krunner {
        my ($win,) = @_;
        $machine->execute("${xdo} key Alt+F2 sleep 1 type $win");
        $machine->execute("${xdo} search --sync --onlyvisible --class krunner sleep 5 key Return");
      }
  
      $machine->waitUntilSucceeds("pgrep plasmashell");
      $machine->succeed("xauth merge ~alice/.Xauthority");    
      $machine->waitForWindow(qr/Desktop.*/);
  
      # Check that logging in has given the user ownership of devices.
      $machine->succeed("getfacl /dev/snd/timer | grep -q alice");
      
      krunner("dolphin");
      $machine->waitForWindow(qr/.*Dolphin/);
      
      krunner("konsole");
      $machine->waitForWindow(qr/.*Konsole/);
      
      krunner("systemsettings5");
      $machine->waitForWindow(qr/.*Settings/);
      $machine->sleep(20);
  
      $machine->execute("${xdo} key Alt+F1 sleep 10");
      $machine->screenshot("screen");
    '';
  })
  