let
  lock = builtins.fromJSON (builtins.readFile ./flake.lock);
  pkgs = import (
    fetchTarball {
      url =
        lock.nodes.nixpkgs.locked.url
        or "https://github.com/NixOS/nixpkgs/archive/${lock.nodes.nixpkgs.locked.rev}.tar.gz";
      sha256 = lock.nodes.nixpkgs.locked.narHash;
    }
  ) {};
in
  pkgs.runCommand "non-reproducible-test" {} ''
    echo ${toString builtins.currentTime} > $out
  ''