anchor.diff:          (nixos { environment.noXlibs = true; }).pkgs.hello;
     };
   
  +  passthru.tests.run = runCommand "hello-test-run" {
  +    nativeBuildInputs = [ self ];
  +  } ''
  +    diff -U3 --color=auto <(hello) <(echo 'Hello, world!')
  +    touch $out
  +  '';
  +
     meta = with lib; {
       description = "A program that produces a familiar, friendly greeting";
       longDescription = ''
  
positive.code: , hello
  }:
  
  stdenv.mkDerivation rec {
    pname = "hello";
    version = "2.12";
  
    src = fetchurl {
      url = "mirror://gnu/hello/${pname}-${version}.tar.gz";
      sha256 = "1ayhp9v4m4rdhjmnl2bq3cibrbqqkgjbl3s7yk2nhlh8vj3ay16g";
    };
  
  
negative.code:       It is fully customizable.
      '';
      homepage = "https://www.gnu.org/software/hello/manual/";
      changelog = "https://git.savannah.gnu.org/cgit/hello.git/plain/NEWS?h=v${self.version}";
      license = licenses.gpl3Plus;
      maintainers = [ maintainers.eelco ];
      platforms = platforms.all;
    };
  })
  