nixos/tests/keymap: add custom layouts test

  mkKeyboardTest = layout: { extraConfig ? {}, tests }: with pkgs.lib; makeTest {

    name = "keymap-${layout}";

    machine.console.keyMap = mkOverride 900 layout;

    machine.services.xserver.desktopManager.xterm.enable = false;

    machine.services.xserver.layout = mkOverride 900 layout;

    machine.imports = [ ./common/x11.nix extraConfig ];

    nodes.machine.console.keyMap = mkOverride 900 layout;

    nodes.machine.services.xserver.desktopManager.xterm.enable = false;

    nodes.machine.services.xserver.layout = mkOverride 900 layout;

    nodes.machine.imports = [ ./common/x11.nix extraConfig ];

    testScript = ''

      import json

    extraConfig.console.keyMap = "de";

    extraConfig.services.xserver.layout = "de";

  };

  custom = {

    tests = {

      us.qwerty = [ "a" "b" "g" "d" "z" "shift-2" "shift-3" ];

      us.expect = [ "a" "b" "g" "d" "z" "@" "#" ];

      greek.qwerty = map (x: "alt_r-${x}")

                     [ "a" "b" "g" "d" "z" ];

      greek.expect = [ "α" "β" "γ" "δ" "ζ" ];

    };

    extraConfig.console.useXkbConfig = true;

    extraConfig.services.xserver.layout = "us-greek";

    extraConfig.services.xserver.extraLayouts.us-greek =

      { description = "US layout with alt-gr greek";

        languages   = [ "eng" ];

        symbolsFile = pkgs.writeText "us-greek" ''

          xkb_symbols "us-greek"

          {

            include "us(basic)"

            include "level3(ralt_switch)"

            key <LatA> { [ a, A, Greek_alpha ] };

            key <LatB> { [ b, B, Greek_beta  ] };

            key <LatG> { [ g, G, Greek_gamma ] };

            key <LatD> { [ d, D, Greek_delta ] };

            key <LatZ> { [ z, Z, Greek_zeta  ] };

          };

        '';

      };

  };

}