these 2 derivations will be built:
  /nix/store/g5gzkdshgspahhy9skjzp9114p9ck0qr-nixos-test-driver-pgtap.drv
  /nix/store/ahdwgqqsd1vz2jgas19j48y3ax1vx12p-vm-test-run-pgtap.drv