these 2 derivations will be built:
  /nix/store/bp9w4xbh19ajyms5fq2sqs2glhq625z2-nixos-test-driver-pgtap.drv
  /nix/store/bssy55dy54030x1nndgqhwb0imcm466g-vm-test-run-pgtap.drv