demo: Add a demo app that runs Plasma in a VM

example/home.nix

@@ -0,0 +1,12 @@
+{ ... }:
+{
+  programs.plasma = {
+    enable = true;
+
+    # A high-level setting:
+    workspace.clickItemTo = "select";
+
+    # A low-level setting:
+    files."baloofilerc"."Basic Settings"."Indexing-Enabled" = false;
+  };
+}

flake.nix

@@ -42,6 +42,20 @@
         {
           default = self.packages.${system}.rc2nix;
 
+          demo = (inputs.nixpkgs.lib.nixosSystem {
+            inherit system;
+            modules = [
+              (import test/demo.nix {
+                pkgs = nixpkgsFor.x86_64-linux;
+                home-manager = inputs.home-manager;
+                module = self.homeManagerModules.plasma;
+                extraPackages = with self.packages.${system}; [
+                  rc2nix
+                ];
+              })
+            ];
+          }).config.system.build.vm;
+
           rc2nix = pkgs.writeShellApplication {
             name = "rc2nix";
             runtimeInputs = with pkgs; [ ruby ];
@@ -53,6 +67,11 @@
         {
           default = self.apps.${system}.rc2nix;
 
+          demo = {
+            type = "app";
+            program = "${self.packages.${system}.demo}/bin/run-plasma-demo-vm";
+          };
+
           rc2nix = {
             type = "app";
             program = "${self.packages.${system}.rc2nix}/bin/rc2nix";

test/demo.nix

@@ -0,0 +1,62 @@
+{ pkgs
+, home-manager
+, module
+, extraPackages
+}:
+
+let
+  homeConfig = {
+    imports = [ ../example/home.nix ];
+  };
+
+  user = import ./user.nix {
+    inherit module home-manager homeConfig;
+  };
+
+in
+{ modulesPath, ... }:
+{
+  imports = [
+    (modulesPath + "/profiles/qemu-guest.nix")
+    (modulesPath + "/virtualisation/qemu-vm.nix")
+    user
+  ];
+
+  config = {
+    networking.hostName = "plasma-demo";
+
+    fileSystems."/" = {
+      device = "/dev/disk/by-label/nixos";
+      fsType = "ext4";
+      autoResize = true;
+    };
+
+    boot = {
+      growPartition = true;
+      loader.timeout = 5;
+      kernelParams = [
+        "console=ttyS0"
+        "boot.shell_on_fail"
+      ];
+    };
+
+    virtualisation = {
+      forwardPorts = [{
+        from = "host";
+        host.port = 2222;
+        guest.port = 22;
+      }];
+    };
+
+    services.xserver = {
+      enable = true;
+      displayManager.sddm.enable = true;
+      displayManager.defaultSession = "plasma";
+      desktopManager.plasma5.enable = true;
+      displayManager.autoLogin.enable = true;
+      displayManager.autoLogin.user = "fake";
+    };
+
+    environment.systemPackages = extraPackages;
+  };
+}

test/user.nix

@@ -19,8 +19,7 @@
     useGlobalPkgs = true;
 
     users.fake = { ... }: {
-      imports = [ module ];
-      config = homeConfig;
+      imports = [ module homeConfig ];
     };
   };
 }