{ pkgs, lib, culr, version, ... }: pkgs.stdenvNoCC.mkDerivation { pname = "culr-tests"; version = "${version}"; nativebuildInputs = [culr]; doCheck = true; checkPhase = '' CULRS="(255,0,0);(0,0,255)" CULR_ORDER=1,0 echo "one two three four" | ${lib.getExe culr} ''; }