TDD for Professionals - Discount example

Basket.java

package module1.exercise.discount;

import java.util.List;

public class Basket {

	private double amount;
	private List<Item> items;

	public Basket(List<Item> itemss) {
		this.items = itemss;
		sumItems();
	}
	
	private void sumItems() {
		for(Item item : items) {
			amount += item.getTotalPrice();
		}
		
	}
	
	public void subtract(double amount) {
		this.amount -= amount;
	}

	public double getAmount() {
		return amount;
	}

	public int qtyOfItems() {
		int qty = 0;
		for(Item item : items) {
			qty+= item.getQty();
		}
		return qty;
	}

	public boolean has(String product) {
		for(Item item : items) {
			if(item.getName().equals(product)) return true;
		}
		
		return false;
	}
	
}

DiscountApplier.java

package module1.exercise.discount;

public class DiscountApplier {

	public void apply(Basket basket) {
		boolean ok = discountPerProduct(basket);
		if(!ok) discountPerAmount(basket);
	}

	private boolean discountPerProduct(Basket basket) {
		if(basket.has("MACBOOK") && basket.has("IPHONE")) {
			basket.subtract(basket.getAmount() * 0.15);
			return true;
		}

		if(basket.has("NOTEBOOK") && basket.has("WINDOWS PHONE")) {
			basket.subtract(basket.getAmount() * 0.12);
			return true;
		}
		
		if(basket.has("XBOX")) {
			basket.subtract(basket.getAmount() * 0.7);
			return true;
		}
		
		return false;
	}

	private void discountPerAmount(Basket basket) {
		
		if(basket.getAmount()<=1000 && basket.qtyOfItems() <= 2) {
			basket.subtract(basket.getAmount() * 0.02);
		}
		
		else if(basket.getAmount() > 3000 && basket.qtyOfItems() < 5 && basket.qtyOfItems() > 2) {
			basket.subtract(basket.getAmount() * 0.05);
		}

		else if(basket.getAmount() > 3000 && basket.qtyOfItems() >= 5) {
			basket.subtract(basket.getAmount() * 0.06);
		}
	}
}

Item.java

package module1.exercise.discount;

public class Item {

	private final String name;
	private final int qty;
	private final double unitPrice;
	
	public Item(String name, int qty, double price) {
		this.name = name;
		this.qty = qty;
		this.unitPrice = price;
	}
	public String getName() {
		return name;
	}
	public int getQty() {
		return qty;
	}
	public double getUnitPrice() {
		return unitPrice;
	}

	public double getTotalPrice() {
		return unitPrice * qty;
	}
	
}