GetByUPC() public method

Returns a product matching the given upc. If no matching product is found an empty product is returned.
public GetByUPC ( string upc ) : ProductDTO
upc string String product upc
return openTill.Domain.DTO.ProductDTO
 public void WhitespaceStringProductGetByUPCException()
 {
     ProductRepository testProductRepository = new ProductRepository();
     testProductRepository.GetByUPC("   ");
 }
 public void NullStringProductGetByUPCException()
 {
     ProductRepository testProductRepository = new ProductRepository();
     testProductRepository.GetByUPC(null);
 }