Testbeds

Stylix provides a suite of virtual machines which can be used to test and preview themes without installing the target to your live system.

These can be particularly helpful for:

• Working on targets before the login screen, since you can avoid closing your editor to see the result.
• Developing for a different desktop environment than the one you normally use.
• Reducing the risk of breaking your system while reviewing pull requests.

Testbeds are also built by GitHub Actions for every pull request. This is less beneficial compared to running them yourself, since it cannot visually check the theme, however it can catch build failures which may have been missed otherwise.

Creation

Testbeds are defined at /modules/«module»/testbeds/«testbed».nix and are are automatically loaded as a NixOS module with options such as stylix.image already defined. The testbed should include any options necessary to install the target and any supporting software - for example, a window manager.

Special Options

Testbeds are given a special set of options which configure for common testbed uses.

• config.stylix.testbed
  • enable defaults to true; allows for conditionally disabling a testbed
  • ui and all of its suboptions are optional. Setting any will enable a graphical environment.
    • command takes a string command to be run once the graphical environment has loaded
    • application takes a desktop application to be run once the graphical environment has loaded. If one of its suboptions is set, all must be.
      • name takes the string name of the desktop application
      • package takes the package which provides the .desktop file

Home Manager

If the target can only be used through Home Manager, you can write a Home Manager module within the NixOS module using the following format:

{ lib, ... }:
{
  home-manager.sharedModules = lib.singleton {
    # Write Home Manager options here
  };
}

Using home-manager.sharedModules is preferred over home-manager.users.guest since it allows us to easily change the username or add additional users in the future.

Once the module is complete, use git add to track the file, then the new packages will be available to use.

Usage

You can list the available testbeds by running this command from anywhere within the repository:

user@host:~$ nix flake show
github:nix-community/stylix
└───packages
    └───x86_64-linux
        ├───docs: package 'stylix-book'
        ├───palette-generator: package 'palette-generator'
        ├───"testbed:gnome:cursorless": package 'testbed-gnome-cursorless'
        ├───"testbed:gnome:dark": package 'testbed-gnome-dark'
        ├───"testbed:gnome:imageless": package 'testbed-gnome-imageless'
        ├───"testbed:gnome:light": package 'testbed-gnome-light'
        ├───"testbed:gnome:schemeless": package 'testbed-gnome-schemeless'
        ├───"testbed:kde:cursorless": package 'testbed-kde-cursorless'
        ├───"testbed:kde:dark": package 'testbed-kde-dark'
        ├───"testbed:kde:imageless": package 'testbed-kde-imageless'
        ├───"testbed:kde:light": package 'testbed-kde-light'
        └───"testbed:kde:schemeless": package 'testbed-kde-schemeless'

(This has been edited down to only the relevant parts.)

To start a testbed, each of which is named in the format testbed:«module»:«testcase», run the following command:

user@host:~$ nix run .#testbed:«module»:«testcase»

Any package with a name not fitting the given format is not a testbed, and may behave differently with this command, or not work at all.

Once the virtual machine starts, a window should open, similar to the screenshot below. The contents of the virtual machine will vary depending on the target you selected earlier.

If the testbed includes a login screen, the guest user should log in automatically when selected. Depending on the software used, you may still be presented with a password prompt - in which case you can leave it blank and proceed by pressing enter.