def test_model(model):
  #TODO load test properly
  model.eval()
  total = 0
  correct = 0
  with torch.no_grad():
    for i, (texts, masks, start_pos, end_pos) in enumerate(dev_data_loader):
        _, probs = model(texts.to(device),
                        mask=masks.to(device),
                        start_positions=torch.tensor(start_pos).to(device),
                        end_positions=torch.tensor(end_pos).to(device))
        start, end = get_best(probs)
        correct += torch.sum((start == start_positions) * (end == end_positions))
        total += len(start)
  print(f'Accuracy on dev data is {correct / total}')