these 2 derivations will be built:
  /nix/store/ndg78lpl2y7klhwpkhm10l69g91qlr2l-nixos-test-driver-pg_cron.drv
  /nix/store/01x7l158hns2hgycbyn7pqcf288ivmc0-vm-test-run-pg_cron.drv