anchor.diff:      headless.services.xserver.enable = false;
     };
   
  -  mkVBoxTest = name: testScript: makeTest {
  +  vboxVMsWithExtpack = mapAttrs createVM {
  +    testExtensionPack.vmFlags = enableExtensionPackVMFlags;
  +  };
  +
  +  mkVBoxTest = useExtensionPack: vms: name: testScript: makeTest {
       name = "virtualbox-${name}";
   
       machine = { lib, config, ... }: {
         imports = let
           mkVMConf = name: val: val.machine // { key = "${name}-config"; };
  -        vmConfigs = mapAttrsToList mkVMConf vboxVMs;
  +        vmConfigs = mapAttrsToList mkVMConf vms;
         in [ ./common/user-account.nix ./common/x11.nix ] ++ vmConfigs;
         virtualisation.memorySize = 2048;
         virtualisation.virtualbox.host.enable = true;
  
positive.code:         return join("\n", grep { $_ !~ /^UUID:/ } split(/\n/, $_[0]))."\n";
        }
  
        ${concatStrings (mapAttrsToList (_: getAttr "testSubs") vboxVMs)}
  
        $machine->waitForX;
  
  
negative.code:     '';
  
      meta = with pkgs.stdenv.lib.maintainers; {
        maintainers = [ aszlig wkennington cdepillabout ];
      };
    };
  
  in mapAttrs (mkVBoxTest false vboxVMs) {
    simple-gui = ''
      createVM_simple;
      $machine->succeed(ru "VirtualBox &");
  