How to run flask along side my tests in PyTest?

Solution

@pytest.mark.fixture(scope="session", autouse=True)
def fake_api():
    app = ...
    port = random.randint(1025, 65535)  # here's hoping no one is on that port
    t = threading.Thread(target=lambda: app.run(debug=True, port=port))
    t.start()
    yield port
    # TODO: implement cleanly terminating the thread here :)