these 2 derivations will be built:
  /nix/store/jhh3951w8nq0rhzgk892p0b069s8p8h8-nixos-test-driver-postgis.drv
  /nix/store/ykyfrkh9hgwc8nzk7cbhsfhlzjdz7lbi-vm-test-run-postgis.drv