强大的Mockito测试框架
1自动生成Mock类
在需要Mock的属性上标记@Mock注解,然后@RunWith(MockitoJUnitRunner.class)或者在setUp()方法中显示调用MockitoAnnotations.initMocks(this);生成Mock类即可。
2自动注入Mock类到被测试类
只要在被测试类上标记@InjectMocks,Mockito就会自动将标记@Mock、@Spy等注解的属性值注入到被测试类中。
- import static org.mockito.Mockito.when;
- import java.util.Collections;
- import java.util.List;
- import javax.annotation.Resource;
- import org.junit.Assert;
- import org.junit.Before;
- import org.junit.Test;
- import org.junit.runner.RunWith;
- import org.mockito.InjectMocks;
- import org.mockito.Mock;
- import org.mockito.MockitoAnnotations;
- importorg.springframework.test.context.ContextConfiguration;
- import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
- import com.cdai.ssi.user.dao.UserDao;
- import com.cdai.ssi.user.domain.UserDomain;
- import com.cdai.ssi.user.dto.UserDto;
- importcom.cdai.ssi.user.service.UserService;
- @RunWith(SpringJUnit4ClassRunner.class)
- @ContextConfiguration({"classpath:spring/spring-config.xml"})
- public class UserServiceTest {
- @InjectMocks
- @Resource(name= "userService")
- privateUserService userService;
- @Mock
- privateUserDao userDao;
- @Before
- publicvoid setUp() {
- MockitoAnnotations.initMocks(this);
- }
- @Test
- publicvoid testQueryAll() {
- when(userDao.selectAll()).
- thenReturn(Collections.<UserDomain>emptyList());
- List<UserDto>dtoList = userService.queryAll();
- Assert.assertTrue(dtoList.isEmpty());
- }
- }
@InjectMocks的问题是:如果被测试类是代理类,那么注入会失效。比如上面的UserService如果是事务或者其他AOP代理类,那么进入@Test方法时UserService中的DAO属性不会被Mock类替换。
3 Mock方法定制再也不用录制、播放了
Mockito的Mock方法定制可读性很强,而且也不需要像EasyMock那样录制播放,定制后就可以使用。
例如:
when(userDao.selectAll()).
thenReturn(Collections.<UserDomain>emptyList());
4有些方法想Mock定制,有些想调用真实方法
因为@Mock针对接口生成Mock类,所以我们是没法调用到真实的实现类的方法。可以使用@Spy注解标注属性,并且标注@Resource注解让Spring注入真实实现类,那么Mockito就会自动生成Spy类。
例如:
@InjectMocks
@Resource(name ="userService")
privateUserService userService;
@Spy
@Resource
privateUserDao userDao;
Spy类就可以满足我们的要求。如果一个方法定制了返回值或者异常,那么就会按照定制的方式被调用执行;如果一个方法没被定制,那么调用的就是真实类的方法。
如果我们定制了一个方法A后,再下一个测试方法中又想调用真实方法,那么只需在方法A被调用前,调用Mockito.reset(spyObject);就行了。
- import static org.mockito.Mockito.when;
- import org.mockito.Mockito;
- public class TestMockObject implementsITestMock {
- publicstatic void main(String[] args) {
- ITestMockmock = Mockito.mock(TestMockObject.class);
- System.out.println(mock.test1());
- System.out.println(mock.test2());
- ITestMockspy = Mockito.spy(new TestMockObject());
- System.out.println(spy.test1());
- System.out.println(spy.test2());
- when(spy.test1()).thenReturn(100);
- System.out.println(spy.test1());
- Mockito.reset(spy);
- System.out.println(spy.test1());
- System.out.println(spy.test2());
- when(spy.test1()).thenReturn(104);
- System.out.println(spy.test1());
- }
- @Override
- publicint test1() {
- System.out.print("RealTest1()!!! - ");
- return1;
- }
- @Override
- publicint test2() {
- System.out.print("RealTest2()!!! - ");
- return2;
- }
- }
输出为:
0
0
Real Test1()!!! - 1
Real Test2()!!! - 2
Real Test1()!!! - 100
Real Test1()!!! - 1
Real Test2()!!! - 2
Real Test1()!!! - 104
要注意的是,对Spy对象的方法定制有时需要用另一种方法:
===============================================================================
Importantgotcha on spying real objects!
Sometimes it's impossible to usewhen(Object) for stubbing spies. Example:
List list = new LinkedList();
List spy = spy(list);
//Impossible: real method is called so spy.get(0) throwsIndexOutOfBoundsException (the list is yet empty)
when(spy.get(0)).thenReturn("foo");
//You have to use doReturn() for stubbing
doReturn("foo").when(spy).get(0);
===============================================================================
因为用when(spy.f1())会导致f1()方法被真正执行,所以就需要另一种写法。
参考资料
Mockito文档
http://mockito.googlecode.com/svn/branches/1.6/javadoc/org/mockito/Mockito.html