public void ChangeStockTest()
{
ProductChangeStockModel mock = new ProductChangeStockModel();
OkObjectResult result = (OkObjectResult)Controller.GetWithSpecifications(4);
Product resultItems = (Product)result.Value;
Specification[] specifications = resultItems.Specifications.ToArray();
mock.Product = resultItems;
mock.NewStock = resultItems.Stock;
OkResult resulttest = (OkResult)Controller.ChangeStock(mock);
Assert.IsInstanceOfType(resulttest, typeof(OkResult));
}