public void model_save_method_is_not_called_if_product_exists() { var product = new Product { Code = "A1", Description = "A1 Desc", Price = 1.0 }; mockProductModel.Stub(p => p.ProductExists(product)).IgnoreArguments().Return(true); RaiseAddButtonPressed(product); mockProductModel.AssertWasNotCalled(m => m.Save(product)); }