GUI testing is not unit testing with buttons attached. As a Qt developer, I can cover a lot with Qt Test: model logic, signal-slot behavior, validation rules, serialization, request construction, response handling, and all the other places where application behavior is accessible directly from code.

Squish solves a different problem. It drives the running application, interacts with the actual GUI, reads runtime object properties, and verifies what the user-facing application is doing after the event loop, QML layer, widgets, focus handling, and platform integration all get involved.

That difference is not academic. A Qt Test case can tell me that the logic behind a login state works; a Squish test can tell me that the login dialog actually appears, can be closed, and leaves the application in the expected visible state.

Why Squish still matters in Qt projects

Squish matters when the GUI itself becomes part of the product contract.…