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;
     }  

 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;
     }  

　　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.