Add more real-world tests

Taken from the https://github.com/kamadorueda/rfc-0101/ repository

Author: piegamesde

src/alejandra/tests/cases/idioms_lib_2/in.nix

@@ -0,0 +1,350 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  inherit (config.boot) kernelPatches;
+  inherit (config.boot.kernel) features randstructSeed;
+  inherit (config.boot.kernelPackages) kernel;
+
+  kernelModulesConf = pkgs.writeText "nixos.conf"
+    ''
+      ${concatStringsSep "\n" config.boot.kernelModules}
+    '';
+
+in
+
+{
+
+  ###### interface
+
+  options = {
+
+    boot.kernel.features = mkOption {
+      default = {};
+      example = literalExpression "{ debug = true; }";
+      internal = true;
+      description = ''
+        This option allows to enable or disable certain kernel features.
+        It's not API, because it's about kernel feature sets, that
+        make sense for specific use cases. Mostly along with programs,
+        which would have separate nixos options.
+        `grep features pkgs/os-specific/linux/kernel/common-config.nix`
+      '';
+    };
+
+    boot.kernelPackages = mkOption {
+      default = pkgs.linuxPackages;
+      type = types.unspecified // { merge = mergeEqualOption; };
+      apply = kernelPackages: kernelPackages.extend (self: super: {
+        kernel = super.kernel.override (originalArgs: {
+          inherit randstructSeed;
+          kernelPatches = (originalArgs.kernelPatches or []) ++ kernelPatches;
+          features = lib.recursiveUpdate super.kernel.features features;
+        });
+      });
+      # We don't want to evaluate all of linuxPackages for the manual
+      # - some of it might not even evaluate correctly.
+      defaultText = literalExpression "pkgs.linuxPackages";
+      example = literalExpression "pkgs.linuxKernel.packages.linux_5_10";
+      description = ''
+        This option allows you to override the Linux kernel used by
+        NixOS.  Since things like external kernel module packages are
+        tied to the kernel you're using, it also overrides those.
+        This option is a function that takes Nixpkgs as an argument
+        (as a convenience), and returns an attribute set containing at
+        the very least an attribute <varname>kernel</varname>.
+        Additional attributes may be needed depending on your
+        configuration.  For instance, if you use the NVIDIA X driver,
+        then it also needs to contain an attribute
+        <varname>nvidia_x11</varname>.
+      '';
+    };
+
+    boot.kernelPatches = mkOption {
+      type = types.listOf types.attrs;
+      default = [];
+      example = literalExpression "[ pkgs.kernelPatches.ubuntu_fan_4_4 ]";
+      description = "A list of additional patches to apply to the kernel.";
+    };
+
+    boot.kernel.randstructSeed = mkOption {
+      type = types.str;
+      default = "";
+      example = "my secret seed";
+      description = ''
+        Provides a custom seed for the <varname>RANDSTRUCT</varname> security
+        option of the Linux kernel. Note that <varname>RANDSTRUCT</varname> is
+        only enabled in NixOS hardened kernels. Using a custom seed requires
+        building the kernel and dependent packages locally, since this
+        customization happens at build time.
+      '';
+    };
+
+    boot.kernelParams = mkOption {
+      type = types.listOf (types.strMatching ''([^"[:space:]]|"[^"]*")+'' // {
+        name = "kernelParam";
+        description = "string, with spaces inside double quotes";
+      });
+      default = [ ];
+      description = "Parameters added to the kernel command line.";
+    };
+
+    boot.consoleLogLevel = mkOption {
+      type = types.int;
+      default = 4;
+      description = ''
+        The kernel console <literal>loglevel</literal>. All Kernel Messages with a log level smaller
+        than this setting will be printed to the console.
+      '';
+    };
+
+    boot.vesa = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        (Deprecated) This option, if set, activates the VESA 800x600 video
+        mode on boot and disables kernel modesetting. It is equivalent to
+        specifying <literal>[ "vga=0x317" "nomodeset" ]</literal> in the
+        <option>boot.kernelParams</option> option. This option is
+        deprecated as of 2020: Xorg now works better with modesetting, and
+        you might want a different VESA vga setting, anyway.
+      '';
+    };
+
+    boot.extraModulePackages = mkOption {
+      type = types.listOf types.package;
+      default = [];
+      example = literalExpression "[ config.boot.kernelPackages.nvidia_x11 ]";
+      description = "A list of additional packages supplying kernel modules.";
+    };
+
+    boot.kernelModules = mkOption {
+      type = types.listOf types.str;
+      default = [];
+      description = ''
+        The set of kernel modules to be loaded in the second stage of
+        the boot process.  Note that modules that are needed to
+        mount the root file system should be added to
+        <option>boot.initrd.availableKernelModules</option> or
+        <option>boot.initrd.kernelModules</option>.
+      '';
+    };
+
+    boot.initrd.availableKernelModules = mkOption {
+      type = types.listOf types.str;
+      default = [];
+      example = [ "sata_nv" "ext3" ];
+      description = ''
+        The set of kernel modules in the initial ramdisk used during the
+        boot process.  This set must include all modules necessary for
+        mounting the root device.  That is, it should include modules
+        for the physical device (e.g., SCSI drivers) and for the file
+        system (e.g., ext3).  The set specified here is automatically
+        closed under the module dependency relation, i.e., all
+        dependencies of the modules list here are included
+        automatically.  The modules listed here are available in the
+        initrd, but are only loaded on demand (e.g., the ext3 module is
+        loaded automatically when an ext3 filesystem is mounted, and
+        modules for PCI devices are loaded when they match the PCI ID
+        of a device in your system).  To force a module to be loaded,
+        include it in <option>boot.initrd.kernelModules</option>.
+      '';
+    };
+
+    boot.initrd.kernelModules = mkOption {
+      type = types.listOf types.str;
+      default = [];
+      description = "List of modules that are always loaded by the initrd.";
+    };
+
+    boot.initrd.includeDefaultModules = mkOption {
+      type = types.bool;
+      default = true;
+      description = ''
+        This option, if set, adds a collection of default kernel modules
+        to <option>boot.initrd.availableKernelModules</option> and
+        <option>boot.initrd.kernelModules</option>.
+      '';
+    };
+
+    system.modulesTree = mkOption {
+      type = types.listOf types.path;
+      internal = true;
+      default = [];
+      description = ''
+        Tree of kernel modules.  This includes the kernel, plus modules
+        built outside of the kernel.  Combine these into a single tree of
+        symlinks because modprobe only supports one directory.
+      '';
+      # Convert the list of path to only one path.
+      apply = pkgs.aggregateModules;
+    };
+
+    system.requiredKernelConfig = mkOption {
+      default = [];
+      example = literalExpression ''
+        with config.lib.kernelConfig; [
+          (isYes "MODULES")
+          (isEnabled "FB_CON_DECOR")
+          (isEnabled "BLK_DEV_INITRD")
+        ]
+      '';
+      internal = true;
+      type = types.listOf types.attrs;
+      description = ''
+        This option allows modules to specify the kernel config options that
+        must be set (or unset) for the module to work. Please use the
+        lib.kernelConfig functions to build list elements.
+      '';
+    };
+
+  };
+
+
+  ###### implementation
+
+  config = mkMerge
+    [ (mkIf config.boot.initrd.enable {
+        boot.initrd.availableKernelModules =
+          optionals config.boot.initrd.includeDefaultModules ([
+            # Note: most of these (especially the SATA/PATA modules)
+            # shouldn't be included by default since nixos-generate-config
+            # detects them, but I'm keeping them for now for backwards
+            # compatibility.
+
+            # Some SATA/PATA stuff.
+            "ahci"
+            "sata_nv"
+            "sata_via"
+            "sata_sis"
+            "sata_uli"
+            "ata_piix"
+            "pata_marvell"
+
+            # Standard SCSI stuff.
+            "sd_mod"
+            "sr_mod"
+
+            # SD cards and internal eMMC drives.
+            "mmc_block"
+
+            # Support USB keyboards, in case the boot fails and we only have
+            # a USB keyboard, or for LUKS passphrase prompt.
+            "uhci_hcd"
+            "ehci_hcd"
+            "ehci_pci"
+            "ohci_hcd"
+            "ohci_pci"
+            "xhci_hcd"
+            "xhci_pci"
+            "usbhid"
+            "hid_generic" "hid_lenovo" "hid_apple" "hid_roccat"
+            "hid_logitech_hidpp" "hid_logitech_dj" "hid_microsoft"
+
+          ] ++ optionals pkgs.stdenv.hostPlatform.isx86 [
+            # Misc. x86 keyboard stuff.
+            "pcips2" "atkbd" "i8042"
+
+            # x86 RTC needed by the stage 2 init script.
+            "rtc_cmos"
+          ]);
+
+        boot.initrd.kernelModules =
+          optionals config.boot.initrd.includeDefaultModules [
+            # For LVM.
+            "dm_mod"
+          ];
+      })
+
+      (mkIf (!config.boot.isContainer) {
+        system.build = { inherit kernel; };
+
+        system.modulesTree = [ kernel ] ++ config.boot.extraModulePackages;
+
+        # Implement consoleLogLevel both in early boot and using sysctl
+        # (so you don't need to reboot to have changes take effect).
+        boot.kernelParams =
+          [ "loglevel=${toString config.boot.consoleLogLevel}" ] ++
+          optionals config.boot.vesa [ "vga=0x317" "nomodeset" ];
+
+        boot.kernel.sysctl."kernel.printk" = mkDefault config.boot.consoleLogLevel;
+
+        boot.kernelModules = [ "loop" "atkbd" ];
+
+        # The Linux kernel >= 2.6.27 provides firmware.
+        hardware.firmware = [ kernel ];
+
+        # Create /etc/modules-load.d/nixos.conf, which is read by
+        # systemd-modules-load.service to load required kernel modules.
+        environment.etc =
+          { "modules-load.d/nixos.conf".source = kernelModulesConf;
+          };
+
+        systemd.services.systemd-modules-load =
+          { wantedBy = [ "multi-user.target" ];
+            restartTriggers = [ kernelModulesConf ];
+            serviceConfig =
+              { # Ignore failed module loads.  Typically some of the
+                # modules in ‘boot.kernelModules’ are "nice to have but
+                # not required" (e.g. acpi-cpufreq), so we don't want to
+                # barf on those.
+                SuccessExitStatus = "0 1";
+              };
+          };
+
+        lib.kernelConfig = {
+          isYes = option: {
+            assertion = config: config.isYes option;
+            message = "CONFIG_${option} is not yes!";
+            configLine = "CONFIG_${option}=y";
+          };
+
+          isNo = option: {
+            assertion = config: config.isNo option;
+            message = "CONFIG_${option} is not no!";
+            configLine = "CONFIG_${option}=n";
+          };
+
+          isModule = option: {
+            assertion = config: config.isModule option;
+            message = "CONFIG_${option} is not built as a module!";
+            configLine = "CONFIG_${option}=m";
+          };
+
+          ### Usually you will just want to use these two
+          # True if yes or module
+          isEnabled = option: {
+            assertion = config: config.isEnabled option;
+            message = "CONFIG_${option} is not enabled!";
+            configLine = "CONFIG_${option}=y";
+          };
+
+          # True if no or omitted
+          isDisabled = option: {
+            assertion = config: config.isDisabled option;
+            message = "CONFIG_${option} is not disabled!";
+            configLine = "CONFIG_${option}=n";
+          };
+        };
+
+        # The config options that all modules can depend upon
+        system.requiredKernelConfig = with config.lib.kernelConfig;
+          [
+            # !!! Should this really be needed?
+            (isYes "MODULES")
+            (isYes "BINFMT_ELF")
+          ] ++ (optional (randstructSeed != "") (isYes "GCC_PLUGIN_RANDSTRUCT"));
+
+        # nixpkgs kernels are assumed to have all required features
+        assertions = if config.boot.kernelPackages.kernel ? features then [] else
+          let cfg = config.boot.kernelPackages.kernel.config; in map (attrs:
+            { assertion = attrs.assertion cfg; inherit (attrs) message; }
+          ) config.system.requiredKernelConfig;
+
+      })
+
+    ];
+
+}