Testing a Limn UI without a display: a SceneDriver that clicks, types and presses keys through a scene's window input, a headless UI runtime and backend, stub windows, fixed text rulers and the accessibility contracts the toolkit's own widgets are held to. Depends on limn-toolkit only, and on no test framework.

The showcase: every widget, the charts, the media player and the 3D viewport in one window. An application, not a library — nothing should depend on it.