public void CalculatesTotalPrice(
            [Frozen] IOrderPriceService orderPriceService,
            [Frozen] IShippingPriceCalculator shippingPriceCalculator,
            TotalPriceCalculator sut)
        {
            orderPriceService.GetPrice().Returns(45);
            shippingPriceCalculator.Calculate().Returns(5);
            var result = sut.Calculate();

            result.Should().Be(50);
        }
 public int Calculate()
 {
     return(_orderPriceService.GetPrice() + _shippingPriceCalculator.Calculate());
 }