these 2 derivations will be built:
  /nix/store/9c7x282hjxvm7ispwbkygxg1gm13yjyv-nixos-test-driver-pgtap.drv
  /nix/store/pjv9mxg3m294gw8pkw22n2vyzdvgjh27-vm-test-run-pgtap.drv