anchor.diff:          # Variables that are substituted within the libvirt XML files
           testid="$(basename "$out")"
           testid="''${testid%%-*}"
  +        testid="''${testid:0:7}"
           build="$(pwd)/build"
           uid="$(id -u)"
           gid="$(id -g)"
  
positive.code:   config = {
  
      libvirt.test.instances.${cfg.test-driver.hostName} = {
        libvirt.name = mkForce "@testid@";
        nixos.modules = cfg.test-driver.extraModules ++ [{
          systemd.services.test-script = {
            wantedBy = [ "multi-user.target" ];
  
negative.code:           mappedGid = "@gid@";
            rootPath = "root-${name}";
          };
          name = "dom-@testid@-${name}";
          uuid = null;
          netdevs.eth0 = {
            mac = null;
  