these 2 derivations will be built:
  /nix/store/bpay280bpzr1p79fj5zzcavsrdz6240m-nixos-test-driver-pg_net.drv
  /nix/store/dfyqd8q32g10vv0j8caqjf96vd0d1x2y-vm-test-run-pg_net.drv