public void ShouldNotRegisterNewStockIfItExists()
        {
            //Arrange
            var stockTableRepository = Substitute.For<IStockTableRepository>();
            StocksService stockService = new StocksService(stockTableRepository);
            StockRegistrationInfo args = new StockRegistrationInfo();
            args.Type = "StockTypeA";
            args.Price = 10;

            //Act
            stockService.RegisterNewStock(args);

            stockTableRepository.Contains(Arg.Is<StockEntity>(w =>
            w.Type == args.Type
            && w.Price == args.Price)).Returns(true);
            stockService.RegisterNewStock(args);

        }
        public void ShouldRegisterNewStock()
        {
            //Arrange
            var stockTableRepository = Substitute.For<IStockTableRepository>();
            StocksService stockService = new StocksService(stockTableRepository);
            StockRegistrationInfo args = new StockRegistrationInfo();
            args.Type = "StockTypeA";
            args.Price = 10;

            //Act
            var stockId = stockService.RegisterNewStock(args);

            //Assert
            stockTableRepository.Received(1).Add(Arg.Is<StockEntity>(w =>
            w.Type == args.Type
            && w.Price == args.Price));
            stockTableRepository.Received(1).SaveChanges();
        }