ShoppingBasket.scala

case class Product(id: Int, price: Int, inStock: Boolean)

case class Basket(productIds: List[Int])

trait ProductRepo {
  def getProduct(productId: Int): Product
}

trait ShoppingBasketRepo {
  def getShoppingBasket(basketId: Int): Basket
}

object Application extends App {
  val productRepo: ProductRepo       = ??? // Assume this is implemented
  val basketRepo: ShoppingBasketRepo = ??? // Assume this is implemented

  def getBasketTotal(basketId: Int, inStockItemsOnly: Boolean): Int = {
    ??? // Todo: Implement
  }
}