anchor.diff:          ''); # */
   
       tests.evalNixpkgs =
  -      { nixpkgs ? { outPath = pkgs.lib.cleanSource <nixpkgs>; revCount = 1234; shortRev = "abcdef"; } }:
         import <nixpkgs/pkgs/top-level/make-tarball.nix> {
           inherit nixpkgs;
           inherit pkgs;
  
positive.code:       };
  
      tests.evalNixOS =
        { nixpkgs ? { outPath = pkgs.lib.cleanSource <nixpkgs>; revCount = 1234; shortRev = "abcdef"; } }:
        pkgs.runCommand "eval-nixos" { buildInputs = [ build.x86_64-linux ]; }
          ''
            export NIX_DB_DIR=$TMPDIR
  
negative.code: { nix ? { outPath = ./.; revCount = 1234; shortRev = "abcdef"; }
  , nixpkgs ? { outPath = <nixpkgs>; revCount = 1234; shortRev = "abcdef"; }
  , officialRelease ? false
  }:
  
  