these 2 derivations will be built:
  /nix/store/5pmvwwcagk7f4s74k0fn0iq850jw1zd1-nixos-test-driver-pgtap.drv
  /nix/store/68njllz12cw51d7xjwkrfi6ip1qia3sh-vm-test-run-pgtap.drv