public void Calculate_ShouldReturnDiscountResult_WithCorrectProductsAndModel()
{
// Arrange
Mock <IDateTimeUtil> mockDateTimeUtil = new Mock <IDateTimeUtil>();
mockDateTimeUtil.Setup(x => x.Now()).Returns(new DateTime(2020, 10, 15));
ITimespanDiscountCalculator timespanDiscountCalculator = new TimespanDiscountCalculator(mockDateTimeUtil.Object);
List <Product> products = new List <Product>()
{
new Product()
{
Id = 1, Name = "Beans", PluralName = "Beans", Price = 0.65m
},
new Product()
{
Id = 2, Name = "Bread", PluralName = "Breads", Price = 0.8m
},
new Product()
{
Id = 3, Name = "Milk", PluralName = "Milk", Price = 1.3m
},
new Product()
{
Id = 4, Name = "Apple", PluralName = "Apples", Price = 1.0m
},
};
TimespanDiscount timespanDiscount = new TimespanDiscount()
{
Id = 1,
BuyingProduct = products[3],
From = new DateTime(2020, 10, 10),
To = new DateTime(2020, 10, 20),
DiscountedProduct = products[3],
DiscountPercentage = 0.1f,
IsActive = true
};
IEnumerable <BasketItem> items = new List <BasketItem>()
{
new BasketItem()
{
Product = new BasketItemProduct()
{
Id = 4, Name = "Apple", PluralName = "Apples", Price = 1.0m
},
Quantity = 1
},
};
// Act
DiscountResult discountResult = timespanDiscountCalculator.Calculate(items, timespanDiscount);
// Assert
Assert.Equal(0.1f, discountResult.DiscountPercentage);
Assert.Equal(0.10m, discountResult.DiscountedPrice);
Assert.Equal("Apples", discountResult.ProductPluralName);
}
public DiscountResult Calculate(IEnumerable <BasketItem> items, TimespanDiscount model)
{
if (items == null)
{
throw new ArgumentNullException(nameof(items));
}
if (model == null)
{
throw new ArgumentNullException(nameof(model));
}
DateTime currentDate = this.dateTimeUtil.Now();
if (currentDate < model.From || currentDate > model.To)
{
return(null);
}
BasketItem buyingProduct = items.FirstOrDefault(p => p.Product.Id == model.BuyingProduct.Id);
if (buyingProduct == null)
{
return(null);
}
BasketItem productForDiscount = items.FirstOrDefault(p => p.Product.Id == model.DiscountedProduct.Id);
if (productForDiscount == null)
{
return(null);
}
decimal currentPrice = productForDiscount.Product.Price;
decimal discountedPrice = (currentPrice * (decimal)model.DiscountPercentage) * productForDiscount.Quantity;
DiscountResult result = new DiscountResult();
result.DiscountedPrice = discountedPrice;
result.ProductPluralName = productForDiscount.Product.PluralName;
result.DiscountPercentage = model.DiscountPercentage;
return(result);
}