these 4 derivations will be built:
  /nix/store/31s70w6lqppf9vqhr5l1hzayfjrggxdi-run-nixos-vm.drv
  /nix/store/jwmlg5aan60jiprx3ki56bzl1qqybzh8-nixos-vm.drv
  /nix/store/bgrd7i80gzlzd53l7bjmm9kimnlarwwd-nixos-test-driver-plpgsql_check.drv
  /nix/store/1f8yspfn91762kkrv7145ixcd01qflaw-vm-test-run-plpgsql_check.drv