Some pytest-qt features, most notably waitSignal and waitSignals, depend on the Qt event loop being active. Calling QApplication.exit() from a test will cause the main event loop and auxiliary event loops to exit and all subsequent event loops to fail to start. This is a problem if some of your tests call an application functionality that calls QApplication.exit().

One solution is to monkeypatch QApplication.exit() in such tests to ensure it was called by the application code but without effectively calling it.

For example:

def test_exit_button(qtbot, monkeypatch):
exit_calls = []
monkeypatch.setattr(QApplication, "exit", lambda: exit_calls.append(1))
button = get_app_exit_button()
qtbot.click(button)
assert exit_calls == [1]


Or using the mock package:

def test_exit_button(qtbot):
with mock.patch.object(QApplication, "exit"):
button = get_app_exit_button()
qtbot.click(button)
assert QApplication.exit.call_count == 1