The aim of this project is to design a very simple object-oriented Auction Engine.
Tracker is an abstract class, implemented using the abc module.
It has 2 methods, create_user and create_item.
Two implementations of Tracker are included:
SimpleTracker uses lists to store new Users and Items.
UniqueTracker does the same, but makes sure no User or Item exists with the same name.
User is a class with name and items_bid attributes.
name cannot be an empty string.
items_bid is a set of the Items on which this User has placed a bid.
Available methods are bid_on, has_bid_on and is_highest_bidder.
Item is a class with name and bids attributes.
name cannot be an empty string.
bids is a list of all the bids placed on this Item.
Available methods are bid and get_winning_bid.
Bid is a class with bidder, price and item attributes.
price must be greater than 0.
bidder and item cannot be None.