these 3 derivations will be built:
  /nix/store/lvy60pddha45dpw61w2nykvys3sbljnj-nixos-vm.drv
  /nix/store/6fv2rlfsb5jlblis0xnlr7853wbzd00k-nixos-test-driver-plpgsql_check.drv
  /nix/store/g25cj3ywca2di1rdsxj4f9kcqfw61xjw-vm-test-run-plpgsql_check.drv