these 2 derivations will be built:
  /nix/store/nwvy2j5nm2mzsckgbrg2mhcsg8yjf3w0-nixos-test-driver-postgis.drv
  /nix/store/44ksqs3i70s02gygrxy6hpd6a2dmk8ii-vm-test-run-postgis.drv