@Test
  public void call_view_with_errors() {
    OperationResult result = new OperationResult();
    result.addError(ValidationError.NAME);

    when(view.fillBill(any(Bill.class))).thenReturn(new Bill());
    when(repository.save(any(Bill.class))).thenReturn(result);

    presenter.save();

    verify(view, times(1)).showError(ValidationError.NAME);
  }