these 3 derivations will be built:
  /nix/store/zsnkhbyr896srpc4pr5bk9j7v4cmk6q7-source.drv
  /nix/store/8g8m75j7xd8nvdbpbzl0zngv5299dqpl-horae-checks-deps-0.1.0.drv
  /nix/store/bi4f579idzzswzp1l5m99v7l2vzbzw8f-horae-tests-0.1.0.drv