anchor.diff:  
       github.wait_for_unit("httpd.service")
   
  -    client.succeed("curl -v https://api.github.com/ >&2")
  +    client.succeed("curl -v https://github.com/ >&2")
       client.succeed("nix registry list | grep nixpkgs")
   
       rev = client.succeed("nix flake info nixpkgs --json | jq -r .revision")
  
positive.code: 
    api = pkgs.runCommand "nixpkgs-flake" {}
      ''
        mkdir -p $out/tarball
  
        dir=NixOS-nixpkgs-${nixpkgs.shortRev}
        cp -prd ${nixpkgs} $dir
        # Set the correct timestamp in the tarball.
        find $dir -print0 | xargs -0 touch -t ${builtins.substring 0 12 nixpkgs.lastModifiedDate}.${builtins.substring 12 2 nixpkgs.lastModifiedDate} --
        tar cfz $out/tarball/${nixpkgs.rev} $dir --hard-dereference
  
        mkdir -p $out/commits
        echo '{"sha": "${nixpkgs.rev}"}' > $out/commits/HEAD
      '';
  
  in
  
  makeTest (
  
negative.code:                   }
                  ];
              };
            services.httpd.virtualHosts."github.com" =
              { forceSSL = true;
                sslServerKey = "${cert}/server.key";
                sslServerCert = "${cert}/server.crt";
                servedDirs =
                  [ { urlPath = "/NixOS/nixpkgs";
                      dir = archive;
                    }
                  ];
              };
          };
  
        client =
  