#[async_test]
async fn test_backpaginate_while_sending() {
    let server = MatrixMockServer::new().await;
    let client = server.client_builder().build().await;

    let event_cache = client.event_cache();
    event_cache.subscribe().unwrap();

    let room_id = room_id!("!omelette:fromage.fr");
    let room = server.sync_joined_room(&client, room_id).await;

    let (room_event_cache, _drop_handles) = room.event_cache().await.unwrap();
    let (events, room_stream) = room_event_cache.subscribe().await.unwrap();

    assert!(events.is_empty());
    assert!(room_stream.is_empty());

    // Send an event in this room with the send queue (so that it's saved in the
    // event cache store).
    server.mock_room_state_encryption().plain().mount().await;
    server.mock_room_send().ok(event_id!("$1")).mock_once().mount().await;
    room.send_queue()
        .send(RoomMessageEventContent::text_plain("Hello, World!").into())
        .await
        .unwrap();

    // Then if I backpaginate,
    let outcome = room_event_cache.pagination().run_backwards_once(20).await.unwrap();
    let BackPaginationOutcome { reached_start, .. } = outcome;

    // The event cache can't know whether this is the start or not, and it shouldn't
    // assume so.
    assert!(reached_start.not());
}