{
  gzip,
  runCommand,
  compressDrv,
}: let
  example = runCommand "sample-drv" {} ''
    mkdir $out
    echo 42 > $out/1.txt
    echo 43 > $out/1.md
    touch $out/2.png
  '';
  drv = compressDrv example {
    formats = ["txt"];
    compressors.gz = "${gzip}/bin/gzip --force --keep --fast {}";
  };
  wrapped = compressDrv drv {
    formats = ["md"];
    compressors.gz = "${gzip}/bin/gzip --force --keep --fast {}";
  };
in
  runCommand "test-compressDrv" {} ''
    set -ex

    ls -l ${drv}
    test -h ${drv}/1.txt
    test -f ${drv}/1.txt.gz
    cmp ${drv}/1.txt <(${gzip}/bin/zcat ${drv}/1.txt.gz)

    test -h ${drv}/2.png
    test ! -a ${drv}/2.png.gz

    # compressDrv always points to the final file, no matter how many times
    # it's been wrapped
    cmp <(readlink -e ${drv}/1.txt) <(readlink -e ${wrapped}/1.txt)

    test -f ${wrapped}/1.txt.gz
    test -f ${wrapped}/1.md.gz
    test ! -f ${drv}/1.md.gz

    mkdir $out
  ''