The checkout kata after 5 stages of connascence removal

Checkout.java

public class Checkout {

	private Money balance = Money.ZERO;
	private MultibuyDiscount discount;

	public Checkout(MultibuyDiscount discount) {
		this.discount = discount.reset();
	}

	public Checkout scan(String sku, Money price) {
		balance = balance.add(price);
		balance = balance.subtract(discount.discountFor(sku));
		return this;
	}

	public Money currentBalance() {
		return balance;
	}

}

CheckoutTests.java

import static org.junit.Assert.assertEquals;

import java.util.Random;

import org.junit.Test;

public class CheckoutTests {

	@Test
	public void basicPrices() {
		Money priceOfA = randomPrice();
		MultibuyDiscount discount = new MultibuyDiscount("A", Money.fromPence(20), 2);
		Checkout checkout = new Checkout(discount);
		Money priceOfB = randomPrice();
		checkout.scan("A", priceOfA).scan("B", priceOfB);
		assertEquals(priceOfA.add(priceOfB), checkout.currentBalance());
	}

	@Test
	public void discountForTwoAs() {
		Money priceOfA = randomPrice();
		Money priceOfB = randomPrice();
		MultibuyDiscount discount = new MultibuyDiscount("A", Money.fromPence(20), 2);
		Checkout checkout = new Checkout(discount);
		checkout.scan("A", priceOfA).scan("B", priceOfB)
				.scan("A", priceOfA);
		Money expectedTotal = priceOfA.add(priceOfA).add(priceOfB)
				.subtract(Money.fromPence(20));
		assertEquals(expectedTotal, checkout.currentBalance());
	}

	@Test
	public void independentCheckouts() {
		Money priceOfA = randomPrice();
		MultibuyDiscount discount = new MultibuyDiscount("A", Money.fromPence(20), 2);
		Checkout checkout1 = new Checkout(discount);
		Checkout checkout2 = new Checkout(discount);
		checkout1.scan("A", priceOfA);
		checkout2.scan("A", priceOfA);
		assertEquals(priceOfA, checkout1.currentBalance());
		assertEquals(priceOfA, checkout2.currentBalance());
	}

	private Money randomPrice() {
		int pence = new Random().nextInt(1000);
		return Money.fromPence(pence);
	}
}

Money.java

public class Money {

	public static final Money ZERO = new Money(0);
	private int pence;

	private Money(int pence) {
		this.pence = pence;
	}

	public static Money fromPence(int pence) {
		return new Money(pence);
	}

	public Money add(Money other) {
		return new Money(pence + other.pence);
	}
	
	public Money subtract(Money other) {
		return new Money(pence - other.pence);
	}
	
	@Override
	public boolean equals(Object other) {
		Money m = (Money) other;
		return pence == m.pence;
	}
	
	@Override
    public int hashCode() {
		return new Integer(pence).hashCode();
    }
	
	@Override
	public String toString() {
		return "" + pence + "p";
	}

}

MultibuyDiscount.java

public class MultibuyDiscount {
	private String watchedSku;
	private Money discount;
	private int trigger;
	private int itemsSeen = 0;

	public MultibuyDiscount(String sku, Money discount, int trigger) {
		this.watchedSku = sku;
		this.discount = discount;
		this.trigger = trigger;
	}

	public Money discountFor(String sku) {
		if (sku.equals(watchedSku))
			itemsSeen++;
		return (itemsSeen == trigger) ? discount : Money.ZERO;
	}

	public MultibuyDiscount reset() {
		return new MultibuyDiscount(watchedSku, discount, trigger);
	}
}