these 2 derivations will be built:
  /nix/store/psdqz039jyapc0yhfjp3l081k9hx6yrv-nixos-test-driver-postgis.drv
  /nix/store/dv7nxvqy1k1njlzq3v58l3aylspi5dn1-vm-test-run-postgis.drv