easymock快速入门

easymock是众多mock之中的很容易用的mock,今天刚开始学习,来个简单的教程.以购物车结算为例子,比如首先是每一个商品项的pojo

public class Item {

	private String name;
	private int quantity;
	
	public Item(String name, int quantity) {
		super();
		this.name = name;
		this.quantity = quantity;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getQuantity() {
		return quantity;
	}
	public void setQuantity(int quantity) {
		this.quantity = quantity;
	}

  然后是购物车的:

public class ShoppingCart {
	
	private String name;
	private Store store = null;
	
	private List<Item> items = new ArrayList();

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public List<Item> getItems() {
		return items;
	}

	public void setItems(List<Item> items) {
		this.items = items;
	}
	
	
	public void addItem(Item item)
	{
		items.add(item);
	}

	
	public void setStore(Store store)
	{
		this.store=store;
	}
	
	public Store getStore()
	{
		return (this.store);
	}
	
	public Double calculateTotal()
	{
		Double total = 0.0;
		 for (Item item : this.items) {
		 total+= (store.getPrice(item.getName()) * item.getQuantity());
		}
		 
		 DecimalFormat decim = new DecimalFormat("0.00");
		 Double price = Double.parseDouble(decim.format(total));
		    
		 return price;
	}

   在这个购物车的计算中,在计算总价格方面,
total+= (store.getPrice(item.getName()) * item.getQuantity());
  这里,依赖了一个额外的对象store,根据store.getPrice()方法求出某个商品的单价,
但这里模拟的是现在根本不知道这个store 是如何实现的,有可能是第三方的,于是
easymock就派上用长了,它可以根据接口去模拟一个实现出来,下面直接看
ShoppingCartTest .java

   

public ShoppingCart cart = null;
	public Store storeMock = null;
	
	@Before
	public void initialize()
	{	
		cart = new ShoppingCart();
		storeMock = EasyMock.createMock(Store.class);
		cart.setStore(storeMock);
	}
	
	
	@Test     
    public void testShoppingCart()
	{
	
		
		EasyMock.expect(storeMock.getPrice("Mead Spiral Bound Notebook, College Rule")).andReturn(5.99);
		EasyMock.expect(storeMock.getPrice("Kindle Fire HD 8.9")).andReturn(499.99);
		
	        //开始使用mock
		EasyMock.replay(storeMock);
				
		Item item1 = new Item("Mead Spiral Bound Notebook, College Rule", 3);
		Item item2 = new Item("Kindle Fire HD 8.9",1);
		
		cart.addItem(item1);
		cart.addItem(item2);
		
		double total = cart.calculateTotal();
		
		System.out.println("Total price of items in shopping cart: $"+total);
		assertEquals("Result",505.96, total,0);
	}
	
	@After
	public void cleanup() 
	{
		cart=null;
		storeMock=null;
	}
    

   同junit一样,在before中,
@Before
public void initialize()
{
cart = new ShoppingCart();
storeMock = EasyMock.createMock(Store.class);
cart.setStore(storeMock);
}
  
storeMock = EasyMock.createMock(Store.class);就可以模拟一个实现出来了,
  然后
EasyMock.expect(storeMock.getPrice("Mead Spiral Bound Notebook, College Rule")).andReturn(5.99);
这里,使用easymock的断言机制,断言出这个属的单价是5.99,然后记得使用
EasyMock.replay(storeMock);就可以在真正的测试中,使用store这个对象了;最后记得cleanup中清理下.
     简单来说,mock系列框架的大概原理就这样了,接下来就是深入的学习