public void GetAmount_WhenItemsArePassed_ShouldApplyAllRateManagers()
{
//Arrange
var promotionManager = new Mock <IPromotionManager>();
var cartItemsMockedData = new CartItems();
var items = cartItemsMockedData.GetAll();
List <List <CartItem> > capturedItems = new List <List <CartItem> >();
promotionManager.Setup(m => m.GetPromotionAmount(Capture.In(capturedItems))).Returns(100);
var sut = GenerateSUT(promotionManager);
//Act
var amount = sut.GetAmount(items);
//Assert
Assert.Single(capturedItems);
var expectedAmount = 100 + capturedItems[0].Sum(m => m.GetAmount());
Assert.Equal(expectedAmount, amount);
}