Add test VM (#982)

This gives me a way to quickly test changes to PaperWM, such as pull
requests, without touching my existing configuration.

Ideally, this config can also be adapted to test combinations of PaperWM
settings (see programs.dconf = ... in vm.nix), maybe automate testing
too!

.gitignore

@@ -8,3 +8,6 @@ [email protected]
 node_modules/
 package.json
 package-lock.json
+
+# generated disk image for test VM
+nixos.qcow2

README.md

@@ -37,17 +37,33 @@ from the repository. The installer will create a link to the repo in
 >
 > After logging back in, you can then enable PaperWM via the `Extensions` application, or by running the following command from the command-line:
 >
-> ```bash
-> /usr/bin/gnome-extensions enable [email protected]
-> ```
+> `/usr/bin/gnome-extensions enable [email protected]`
+>
 
 > if you have run into issues, delete any older `paperwm@...` symlinks from `~/.local/share/gnome-shell/extensions` and re-run the `install.sh` script.
 
 #### Uninstall PaperWM (if installed via source)
+
 To uninstall simply run `./uninstall.sh`.
 
 Running the extension will automatically install a user config file as described in [User configuration & development](#user-configuration--development).
 
+
+### Try without installing
+
+This repo provides a lightweight VM based on [NixOS](https://nixos.org) to try PaperWM and aid with development. You can launch it if [Nix](https://nixos.org/nix) is installed on your system using this command:
+
+```sh
+nix run .\#vm
+```
+
+Alternatively, the VM can also be launched with GPU acceleration, by installing [NixGL](https://github.com/nix-community/nixgl) first:
+
+```sh
+nixGLIntel nix run .\#vm -- -device virtio-gpu-gl -display gtk,gl=on
+# or nixGLNvidia depending on your host GPU
+```
+
 ## Contributing
 Users are encouraged to submit [issues](https://github.com/paperwm/PaperWM/issues/new/choose) and [Pull Requests](https://github.com/paperwm/PaperWM/pulls)!
 

flake.nix

@@ -8,5 +8,25 @@
     let pkgs = import nixpkgs { inherit system; };
     in
     { packages.default = pkgs.callPackage ./default.nix {};
-    });
+      packages.vm = let hostConfig = self.nixosConfigurations.testbox.config;
+                        localConfig = hostConfig // {
+                          virtualisation = hostConfig.virtualisation // {
+                            host.pkgs = pkgs;   # Use host system's Qemu
+                          };
+                        };
+                     in localConfig.system.build.vm;
+    }) // {
+      nixosConfigurations."testbox" =
+        let system = "x86_64-linux";
+        in nixpkgs.lib.nixosSystem {
+          inherit system;
+          modules = [
+            ./vm.nix
+            { nixpkgs.overlays = [
+                (s: super: { paperwm = self.packages.${system}.default; })
+              ];
+            }
+          ];
+        };
+    };
 }

vm.nix

@@ -0,0 +1,48 @@
+{ pkgs, config, lib, ... }:
+
+{
+  ### Make PaperWM available in system environment
+  environment.systemPackages = with pkgs;
+  [ paperwm
+  ];
+
+  ### Set graphical session to auto-login GNOME
+  services.xserver =
+  { enable = true;
+    displayManager.autoLogin =
+    { enable = true;
+      user = "user";
+    };
+    displayManager.gdm.enable = true;
+    desktopManager.gnome.enable = true;
+  };
+
+  ### Set dconf to enable PaperWM out of the box
+  programs.dconf =
+  { enable = true;
+    profiles."user".databases = [
+      { settings =
+        { "org/gnome/shell" =
+          { enabled-extensions = [ "[email protected]" ];
+          };
+        };
+      }
+    ];
+  };
+
+  ### Set default user
+  users.users."user" =
+  { isNormalUser = true;
+    createHome = true;
+    home = "/home";
+    description = "PaperWM test user";
+    extraGroups = [ "wheel" ];
+    password = "paperwm";
+  };
+
+  ### No-password sudo
+  security.sudo =
+  { enable = true;
+    extraConfig = "%wheel ALL=(ALL) NOPASSWD: ALL";
+  };
+}