public async Task Calculate_Card_Total() { var options = new DbContextOptionsBuilder <SportStoreDbContext>() .UseInMemoryDatabase(databaseName: "Calculate_Card_Total") .Options; var cardItem1 = new CardItem() { Product = new Product() { Id = 1, Price = 5.0M, Name = "P1" }, Quantity = 1 }; var cardItem2 = new CardItem() { Product = new Product() { Id = 2, Price = 5.0M, Name = "P2" }, Quantity = 2 }; using (var context = new SportStoreDbContext(options)) { await context.CardItems.AddAsync(cardItem1); await context.CardItems.AddAsync(cardItem2); await context.SaveChangesAsync(); var service = new CardService(context); var resultSum = await service.ComputeTotalValue(); Assert.Equal(15.0M, resultSum); } }