these 2 derivations will be built:
  /nix/store/5ws6icj39sv3dqkpgpz7drbmbf9vc92f-nixos-test-driver-pg_cron.drv
  /nix/store/fnnbrl08ahzy13j84padycbjfyvs09kw-vm-test-run-pg_cron.drv