{ pkgs, lib, stdenv, ... }:

lib.runTests {
  # Merging two non-list definitions must still result in an error
  # about a conflicting definition.
  test-unitOption-merging-non-lists-conflict =
    let nixos = pkgs.nixos {
        system.stateVersion = lib.trivial.release;
        systemd.services.systemd-test-nixos = {
          serviceConfig = lib.mkMerge [
            { StateDirectory = "foo"; }
            { StateDirectory = "bar"; }
          ];
        };
      };
    in {
    expr = (builtins.tryEval (nixos.config.systemd.services.systemd-test-nixos.serviceConfig.StateDirectory)).success;
    expected = false;
  };

  # Merging must lift non-list definitions to a list
  # if at least one of them is a list.
  test-unitOption-merging-list-non-list-append =
    let nixos = pkgs.nixos {
        system.stateVersion = lib.trivial.release;
        systemd.services.systemd-test-nixos = {
          serviceConfig = lib.mkMerge [
            { StateDirectory = "foo"; }
            { StateDirectory = ["bar"]; }
          ];
        };
      };
    in {
    expr = nixos.config.systemd.services.systemd-test-nixos.serviceConfig.StateDirectory;
    expected = [ "foo" "bar" ];
  };
}