these 2 derivations will be built:
  /nix/store/5c0lhw6f23j0byvvp0jgmx31fyha6l00-nixos-test-driver-pg_repack.drv
  /nix/store/amyhiid3kr04q9zcfjkl9d01bvgix9hh-vm-test-run-pg_repack.drv