EasyMockTest.java

package com.jinhe.tss.core.util;

import java.io.IOException;

import junit.framework.TestCase;

import org.easymock.EasyMock;

public class EasyMockTest extends TestCase {

	public void testToEuros() throws IOException {
		Currency testObject = new Currency(2.50, "USD");
		Currency expected = new Currency(3.75, "EUR");
		
		ExchangeRate mock = EasyMock.createMock(ExchangeRate.class);
		EasyMock.expect(mock.getRate("USD", "EUR")).andReturn(1.5);
		
		EasyMock.replay(mock);
		Currency actual = testObject.toEuros(mock);
		assertEquals(expected, actual);
	}

}

interface ExchangeRate {
	double getRate(String currency, String outputCurrency) throws IOException;
}

class Currency {

	private String units;
	private long amount;
	private int cents;

	public Currency(double amount, String code) {
		this.units = code;
		this.amount = new Double(amount).longValue();
		this.cents = (int) ((amount * 100.0) % 100);
	}

	public Currency toEuros(ExchangeRate converter) {
		if ("EUR".equals(units))
			return this;
		else {
			double input = amount + cents / 100.0;
			double rate;
			try {
				rate = converter.getRate(units, "EUR");
				double output = input * rate;
				return new Currency(output, "EUR");
			} catch (IOException ex) {
				return null;
			}
		}
	}

	public boolean equals(Object o) {
		if (o instanceof Currency) {
			Currency other = (Currency) o;
			return this.units.equals(other.units)
					&& this.amount == other.amount && this.cents == other.cents;
		}
		return false;
	}

	public String toString() {
		return amount + "." + Math.abs(cents) + " " + units;
	}

}