these 2 derivations will be built:
  /nix/store/gxmi575ll85f9kbgvx958rsyb0b8hgj2-nixos-test-driver-pg_cron.drv
  /nix/store/mnsbzs2bbzgg5xjm3g5wqlffym6jzb5s-vm-test-run-pg_cron.drv