these 2 derivations will be built:
  /nix/store/cr7919rw8qqv5rdzvpwbhgswmvnirn8j-nixos-test-driver-postgis.drv
  /nix/store/3k62ppi0kcwcznwaizwjpp4jqfmapngk-vm-test-run-postgis.drv