these 2 derivations will be built:
  /nix/store/q9hrsc1rwdlp8ynj2fi5h1sc2kchp11g-nixos-test-driver-pg_cron.drv
  /nix/store/psy49ffk88aq4rasvzhljv64c8wxrrn2-vm-test-run-pg_cron.drv