This exercise was to demonstrate how to test driving multiple objects.

The aim was to write the code for a supermarket checkout that can calculate the price of a number of items.

Each item should be priced individually, and the checkout should be able to scan them in any order.

The requirements for the system are as follows:

As a shopper
So I know how much an item costs
I would like to be able to see its price

As a shopper
So that I can buy an item
I would like to be able to scan items at the checkout

As a shopper
So that I know how much to pay
I would like to be able to see a total for all scanned items

As a shopper
So that I know how much to pay
I would like to see all prices correctly formatted (£xx.xx)

Your main focus here should be to follow a rigorous TDD process: RED, GREEN, REFACTOR!