def test_app():
    client = TestClient(app)
    with client.websocket_connect("/") as websocket:
        data = websocket.receive_text()
        assert data == "Hello, world!"


def test_router():
    client = TestClient(app)
    with client.websocket_connect("/router") as websocket:
        data = websocket.receive_text()
        assert data == "Hello, router!"


def test_prefix_router():