these 2 derivations will be built:
  /nix/store/kgxf2k6pb8ilg0g9bv7jzq2bkw0kj2v5-iets-0.1.0.drv
  /nix/store/5l7kzsbwqhnl9fadw1zz5ch9pfswjq2i-iets-partest.drv