these 2 derivations will be built:
  /nix/store/35npds2vq6wjc589hqrka22gb23d5my1-nixos-test-driver-pgtap.drv
  /nix/store/sdq3mvrsn8zsfpp3ql1m2wbmb7jyvhx7-vm-test-run-pgtap.drv