Testing

The test package lets you test a Bellui UI with ordinary go test. It replaces the real app with an in-memory one: windows are never shown, nothing needs a GPU or a display, and tests run on any machine, including CI servers.

A UI test usually does three things:

1. Creates a test app and puts the UI in a test window.
2. Simulates what a user does: taps, typing, dragging.
3. Checks the result, either by reading widget state or by comparing the rendering with a saved golden file.

What the test app provides

test.NewApp creates the app and makes it the current one, so code that calls bellui.CurrentApp() works. It comes with:

• a test driver whose windows live only in memory;
• in-memory preferences, so tests never touch the user’s real settings;
• app storage rooted in the system’s temporary folder;
• its own clipboard;
• a fixed test theme, so results do not depend on the user’s theme settings.

On the test driver, bellui.Do and bellui.DoAndWait run the function straight away and return when it has finished. Code that hands work to the UI thread can be tested without waiting for an event loop.

Prefer test.NewTempApp(t) and test.NewTempWindow(t, content) in tests. They do the same as NewApp and NewWindow, and clean up when the test ends.