ShoppingBasket.java

public class ShoppingBasket {
	
	private final List<Object[]> basket = new ArrayList<>();

	void addItem(String productCode, String productDescription, double price, int quantity) {
		
		Object[] item = new Object[] {
				productCode ,
				productDescription ,
				price ,
				quantity
		};
		
		basket.add(item);
	}

	double total() {
		double total = basket.stream()
				.mapToDouble(i -> (double)i[ShoppingCartTest.PRICE] * (int)i[ShoppingCartTest.QUANTITY])
				.sum();
		return total;
	}
}