Testing that flet app starts, then quit

[clstaudt]

I would like to write a pytest test that checks whether the app starts sucessfully, then ends it after a while. The test should also pass if there is no graphical user interface available (e.g. GitHub CI).

My first attempt was not successful. The app is not terminated and the test runs forever.

def test_app_starts_and_quits():
    # Start the app process
    app_process = subprocess.Popen(["python", "app/app.py"])
    
    # Wait for a few seconds to let the app start
    time.sleep(3)
    
    # Verify the process is still running
    assert app_process.poll() is None
    
    # Terminate the app process
    app_process.terminate()
    
    # Wait for the process to end
    app_process.wait()
    
    # Verify the process has ended

    assert app_process.returncode is not None