nixpkgs/nixos/tests/systemd-initrd-modprobe.nix

import ./make-test-python.nix ({ lib, pkgs, ... }: {
  name = "systemd-initrd-modprobe";

  nodes.machine = { pkgs, ... }: {
    testing.initrdBackdoor = true;
    boot.initrd.systemd.enable = true;
    boot.initrd.kernelModules = [ "tcp_hybla" ]; # Load module in initrd.
    boot.extraModprobeConfig = ''
      options tcp_hybla rtt0=42
    '';
  };

  testScript = ''
    machine.wait_for_unit("initrd.target")
    rtt = machine.succeed("cat /sys/module/tcp_hybla/parameters/rtt0")
    assert int(rtt) == 42, "Parameter should be respected for initrd kernel modules"

    # Make sure it sticks in stage 2
    machine.switch_root()
    machine.wait_for_unit("multi-user.target")
    rtt = machine.succeed("cat /sys/module/tcp_hybla/parameters/rtt0")
    assert int(rtt) == 42, "Parameter should be respected for initrd kernel modules"
  '';
})