these 2 derivations will be built:
  /nix/store/3znmq4x8m35f7mwk1n79sm1sr2hmajah-iets-0.1.0.drv
  /nix/store/10wnmvlziv7mzyk74gq6jq5h8i7k9sjq-iets-langtests.drv