Plan to support QtAsyncio apps?

[guilbaudl]

Hello,
I couldn't find any information regarding QtAsyncio support. Is there any plan moving forward to support apps running thanks to QtAsyncio?

Doc for QtAsyncio

Regards

[nicoddemus]

Hi @guilbaudl,

No plans so far, in fact I just learned it existed. Seems to be in preview, but definitely seems interesting!

[guilbaudl]

It is in preview but it is actually part of PySide stable releases, so that would be amazing to try to support it! It is usable so far at least.

[nicoddemus]

It seems the first steps would be to study what QtAsyncio.run (from the minimal example) does under the covers:

if __name__ == "__main__":
    app = QApplication(sys.argv)
    main_window = MainWindow()
    main_window.show()

    QtAsyncio.run(handle_sigint=True)

I believe it creates the Qt-specific event loop, and integrate with the QApplication somehow... not sure if that is exposed externally or not (could not find with a quick glance at the docs).

Given QtAsyncio still uses a normal QApplication, one does not even need to extend pytest-qt directly, it should be possible to provide your own qapp fixture that setups the asyncio event loop, and the rest of the pytest-qt would still work normally:

# content of conftest.py

@pytest.fixture
def qapp(qapp: QApplication) -> QApplication:
    # The qapp parameter is the builtin pytest-qt `qapp` fixture.
    # At this point, we need to setup the event loop, etc (what QtAsyncio.run does under the covers),
    # but in a non-blocking manner.
    return qapp

Also, we do not need async test functions, because most of the async events would still happen behind sync events.

For example, a test for the MainWindow from that "minimal example" could look like this initially:

def test_main_window(qtbot):
    main_window = MainWindow()
    qtbot.add_widget(main_window)

    main_window.async_trigger.click()  # This triggers the `async set_text` method.

    def check_text_changed():
        assert main_window.text.text() == "What do you get if you multiply six by nine?"

    qtbot.waitUntil(check_text_changed)

---

Full disclosure, I do not have plans to work on this any time soon, I'm just writing down some quick thoughts in case somebody wants to tackle this.