Choose a testing strategy

Keep assertions at the smallest level that exercises the behavior you need.

Level	Typical assertion	Setup
Model or service	A command changes application state	Plain xUnit
Headless control	Input changes text, selection, layout, or bindings	ProTest xUnit adapter
Rendered output	A border or custom control produces expected pixels	ProTest plus Skia
Native application	An operating-system window exposes accessibility and native menus	Real Appium tooling

Headless tests create Avalonia controls and the dispatcher in memory. A Window participates in layout and input processing without appearing on the desktop. This makes the same suite usable on local machines and CI hosts.

Use the Appium-style helpers to express in-process tests with familiar locators. These helpers still belong to the headless layer; real Appium tests exercise a launched application through native automation.

A practical progression is to test model state first, add headless tests for the controls that connect to it, and add image baselines or native tests for behavior that the earlier layers cannot observe.

Topic reference: Avalonia testing overview.