mockito测试入门

1 mockito介绍和入门

官方：https://github.com/mockito/mockito

入门：

5分钟了解Mockito    http://liuzhijun.iteye.com/blog/1512780

Mockito：一个强大的用于 Java 开发的模拟测试框架   http://www.oschina.net/translate/mockito-a-great-mock-framework-for-java-development

2 spring中正常使用mockito

上demo代码：

 1 @RunWith(SpringJUnit4ClassRunner.class)
 2 @ContextConfiguration(locations = { "classpath:testApplicationContext.xml" })
 3 public class SpringMockitoTest {
 4  
 5     @Mock
 6     private ApiService mockApiService;
 7  
 8     @Before
 9     public void initMocks() {
10         MockitoAnnotations.initMocks(this);
11         when(mockApiService.test()).thenReturn("ok");
12     }
13  
14     @Test
15     public void should_success_when_testApiService() {
16         String result = mockApiService.test();
17         Assert.assertEquals("ok", result);
18     }
19 }
20  
21 @Component
22 public class ApiService {
23  
24     @Autowired
25     private TestApiService testApiService;
26  
27     public String test() {
28         String connect = testApiService.connect();
29         connect += "test";//test自己的业务
30         return connect;
31     }
32 }
33  
34 @Component
35 public class TestApiService {
36     public String connect() {
37         return "error";
38     }
39  
40     public String  findFromDb() {
41         return "db_data";
42     }
43 }

正常使用spring和mockito中，我们把需要的mock的ApiService给mock掉，但是我们更想的是把TestApiService中的connect方法mock掉，这样就可以测试我们自己的代码，也就是ApiService中test方法自己的业务。

3 spring中mock任何容器内对象

上面的demo中，我们如何mock掉TestApiService中的test方法？

因为TestApiService是spring容器管理的bean，并且ApiService中使用到TestApiService，所以我们把ApiService中引用的TestApiService替换成我们的mock对象即可。

Spring框架有个反射工具ReflectionTestUtils，可以把一个对象中属性设置为新值，我们可以使用：

ReflectionTestUtils.setField(apiService, "testApiService", spyTestApiService);

把我们mock的testApiService放到apiService中，这样apiService调用就是我们mock的对象了；但是默认spring中apiService对象是代理对象，不能直接把值设置到属性上，所以我们自己写个小的工具类，在最后如下：

ReflectionTestUtils.setField(AopTargetUtils.getTarget(apiService), "testApiService", spyTestApiService);

完整demo：

 1 @RunWith(SpringJUnit4ClassRunner.class)
 2 @ContextConfiguration(locations = { "classpath:testApplicationContext.xml" })
 3 public class SpringMockitoTest {
 4  
 5     @Autowired
 6     private ApiService apiService;
 7     @Mock
 8     private TestApiService spyTestApiService;
 9     @Autowired
10     private TestApiService testApiService;
11  
12     @Before
13     public void initMocks() throws Exception {
14         MockitoAnnotations.initMocks(this);
15         ReflectionTestUtils.setField(AopTargetUtils.getTarget(apiService), "testApiService", spyTestApiService);
16         when(spyTestApiService.connect()).thenReturn("ok");
17     }
18  
19     @After
20     public void clearMocks() throws Exception {
21         ReflectionTestUtils.setField(AopTargetUtils.getTarget(apiService), "testApiService", testApiService);
22     }
23  
24     @Test
25     public void should_success_when_testApiService() {
26         String result = apiService.test();
27         Assert.assertEquals("oktest", result);
28     }
29 }
30  
31 @Component
32 public class ApiService {
33  
34     @Autowired
35     private TestApiService testApiService;
36  
37     public String test() {
38         String connect = testApiService.connect();
39         connect += "test";//test自己的业务
40         return connect;
41     }
42 }
43  
44 @Component
45 public class TestApiService {
46     public String connect() {
47         return "error";
48     }
49  
50     public String  findFromDb() {
51         return "db_data";
52     }
53 }
54  
55 public class AopTargetUtils {
56     /** 
57      * 获取 目标对象 
58      * @param proxy 代理对象 
59      * @return  
60      * @throws Exception 
61      */
62     public static Object getTarget(Object proxy) throws Exception {  
63         if(!AopUtils.isAopProxy(proxy)) {  
64             return proxy;//不是代理对象  
65         }  
66         if(AopUtils.isJdkDynamicProxy(proxy)) {  
67             return getJdkDynamicProxyTargetObject(proxy);  
68         } else { //cglib  
69             return getCglibProxyTargetObject(proxy);  
70         }  
71     }  
72  
73     private static Object getCglibProxyTargetObject(Object proxy) throws Exception {  
74         Field h = proxy.getClass().getDeclaredField("CGLIB$CALLBACK_0");  
75         h.setAccessible(true);  
76         Object dynamicAdvisedInterceptor = h.get(proxy);  
77         Field advised = dynamicAdvisedInterceptor.getClass().getDeclaredField("advised");  
78         advised.setAccessible(true);  
79         Object target = ((AdvisedSupport)advised.get(dynamicAdvisedInterceptor)).getTargetSource().getTarget();  
80         return target;  
81     }  
82  
83  
84     private static Object getJdkDynamicProxyTargetObject(Object proxy) throws Exception {  
85         Field h = proxy.getClass().getSuperclass().getDeclaredField("h");  
86         h.setAccessible(true);  
87         AopProxy aopProxy = (AopProxy) h.get(proxy);  
88         Field advised = aopProxy.getClass().getDeclaredField("advised");  
89         advised.setAccessible(true);  
90         Object target = ((AdvisedSupport)advised.get(aopProxy)).getTargetSource().getTarget();  
91         return target;  
92     }  
93 }

最后就是注意测试之后要还原现场，把spring对象还原，尤其在跑maven test的时候，否则可能会影响其他人的测试。

作者： syxChina
出处： http://syxchina.cnblogs.com、  www.jingruigroup.com