转载:http://blog.csdn.net/u012881904/article/details/51334747
官网:
API文档:http://docs.mockito.googlecode.com/hg/org/mockito/Mockito.html
项目源码:https://github.com/mockito/mockito
首先添加maven依赖
- <dependency>
- <groupId>org.mockito</groupId>
- <artifactId>mockito-all</artifactId>
- <version>1.9.5</version>
- <scope>test</scope>
- </dependency>
当然mockito需要junit配合使用
- <dependency>
- <groupId>junit</groupId>
- <artifactId>junit</artifactId>
- <version>4.11</version>
- <scope>test</scope>
- </dependency>
然后为了使代码更简洁,最好在测试类中导入静态资源
- import static org.mockito.Mockito.*;
- import static org.junit.Assert.*;
1、验证行为
- @Test
- public void verify_behaviour(){
- //模拟创建一个List对象
- List mock = mock(List.class);
- //使用mock的对象
- mock.add(1);
- mock.clear();
- //验证add(1)和clear()行为是否发生
- verify(mock).add(1);
- verify(mock).clear();
- }
2、模拟我们所期望的结果
- @Test
- public void when_thenReturn(){
- //mock一个Iterator类
- Iterator iterator = mock(Iterator.class);
- //预设当iterator调用next()时第一次返回hello,第n次都返回world
- when(iterator.next()).thenReturn("hello").thenReturn("world");
- //使用mock的对象
- String result = iterator.next() + " " + iterator.next() + " " + iterator.next();
- //验证结果
- assertEquals("hello world world",result);
- }
- @Test(expected = IOException.class)
- public void when_thenThrow() throws IOException {
- OutputStream outputStream = mock(OutputStream.class);
- OutputStreamWriter writer = new OutputStreamWriter(outputStream);
- //预设当流关闭时抛出异常
- doThrow(new IOException()).when(outputStream).close();
- outputStream.close();
- }
3、参数匹配
- @Test
- public void with_arguments(){
- Comparable comparable = mock(Comparable.class);
- //预设根据不同的参数返回不同的结果
- when(comparable.compareTo("Test")).thenReturn(1);
- when(comparable.compareTo("Omg")).thenReturn(2);
- assertEquals(1, comparable.compareTo("Test"));
- assertEquals(2, comparable.compareTo("Omg"));
- //对于没有预设的情况会返回默认值
- assertEquals(0, comparable.compareTo("Not stub"));
- }
除了匹配制定参数外,还可以匹配自己想要的任意参数
- @Test
- public void with_unspecified_arguments(){
- List list = mock(List.class);
- //匹配任意参数
- when(list.get(anyInt())).thenReturn(1);
- when(list.contains(argThat(new IsValid()))).thenReturn(true);
- assertEquals(1, list.get(1));
- assertEquals(1, list.get(999));
- assertTrue(list.contains(1));
- assertTrue(!list.contains(3));
- }
- private class IsValid extends ArgumentMatcher<List>{
- @Override
- public boolean matches(Object o) {
- return o == 1 || o == 2;
- }
- }
需要注意的是如果你使用了参数匹配,那么所有的参数都必须通过matchers来匹配
- @Test
- public void all_arguments_provided_by_matchers(){
- Comparator comparator = mock(Comparator.class);
- comparator.compare("nihao","hello");
- //如果你使用了参数匹配,那么所有的参数都必须通过matchers来匹配
- verify(comparator).compare(anyString(),eq("hello"));
- //下面的为无效的参数匹配使用
- //verify(comparator).compare(anyString(),"hello");
- }
4、验证确切的调用次数
- @Test
- public void verifying_number_of_invocations(){
- List list = mock(List.class);
- list.add(1);
- list.add(2);
- list.add(2);
- list.add(3);
- list.add(3);
- list.add(3);
- //验证是否被调用一次,等效于下面的times(1)
- verify(list).add(1);
- verify(list,times(1)).add(1);
- //验证是否被调用2次
- verify(list,times(2)).add(2);
- //验证是否被调用3次
- verify(list,times(3)).add(3);
- //验证是否从未被调用过
- verify(list,never()).add(4);
- //验证至少调用一次
- verify(list,atLeastOnce()).add(1);
- //验证至少调用2次
- verify(list,atLeast(2)).add(2);
- //验证至多调用3次
- verify(list,atMost(3)).add(3);
- </span>}
5、模拟方法体抛出异常
- @Test(expected = RuntimeException.class)
- public void doThrow_when(){
- List list = mock(List.class);
- doThrow(new RuntimeException()).when(list).add(1);
- list.add(1);
- }
6、验证执行顺序
- @Test
- public void verification_in_order(){
- List list = mock(List.class);
- List list2 = mock(List.class);
- list.add(1);
- list2.add("hello");
- list.add(2);
- list2.add("world");
- //将需要排序的mock对象放入InOrder
- InOrder inOrder = inOrder(list,list2);
- //下面的代码不能颠倒顺序,验证执行顺序
- inOrder.verify(list).add(1);
- inOrder.verify(list2).add("hello");
- inOrder.verify(list).add(2);
- inOrder.verify(list2).add("world");
- }
7、确保模拟对象上无互动发生
- @Test
- public void verify_interaction(){
- List list = mock(List.class);
- List list2 = mock(List.class);
- List list3 = mock(List.class);
- list.add(1);
- verify(list).add(1);
- verify(list,never()).add(2);
- //验证零互动行为
- verifyZeroInteractions(list2,list3);
- }
8、找出冗余的互动(即未被验证到的)
- @Test(expected = NoInteractionsWanted.class)
- public void find_redundant_interaction(){
- List list = mock(List.class);
- list.add(1);
- list.add(2);
- verify(list,times(2)).add(anyInt());
- //检查是否有未被验证的互动行为,因为add(1)和add(2)都会被上面的anyInt()验证到,所以下面的代码会通过
- verifyNoMoreInteractions(list);
- List list2 = mock(List.class);
- list2.add(1);
- list2.add(2);
- verify(list2).add(1);
- //检查是否有未被验证的互动行为,因为add(2)没有被验证,所以下面的代码会失败抛出异常
- verifyNoMoreInteractions(list2);
- }
9、使用注解来快速模拟
在上面的测试中我们在每个测试方法里都mock了一个List对象,为了避免重复的mock,是测试类更具有可读性,我们可以使用下面的注解方式来快速模拟对象:
- @Mock
- private List mockList;
OK,我们再用注解的mock对象试试
- @Test
- public void shorthand(){
- mockList.add(1);
- verify(mockList).add(1);
- }
运行这个测试类你会发现报错了,mock的对象为NULL,为此我们必须在基类中添加初始化mock的代码
- public class MockitoExample2 {
- @Mock
- private List mockList;
- public MockitoExample2(){
- MockitoAnnotations.initMocks(this);
- }
- @Test
- public void shorthand(){
- mockList.add(1);
- verify(mockList).add(1);
- }
- }
或者使用built-in runner:MockitoJUnitRunner
- @RunWith(MockitoJUnitRunner.class)
- public class MockitoExample2 {
- @Mock
- private List mockList;
- @Test
- public void shorthand(){
- mockList.add(1);
- verify(mockList).add(1);
- }
- }
更多的注解还有@Captor,@Spy,@InjectMocks
10、连续调用
- @Test(expected = RuntimeException.class)
- public void consecutive_calls(){
- //模拟连续调用返回期望值,如果分开,则只有最后一个有效
- when(mockList.get(0)).thenReturn(0);
- when(mockList.get(0)).thenReturn(1);
- when(mockList.get(0)).thenReturn(2);
- when(mockList.get(1)).thenReturn(0).thenReturn(1).thenThrow(new RuntimeException());
- assertEquals(2,mockList.get(0));
- assertEquals(2,mockList.get(0));
- assertEquals(0,mockList.get(1));
- assertEquals(1,mockList.get(1));
- //第三次或更多调用都会抛出异常
- mockList.get(1);
- }
11、使用回调生成期望值
- @Test
- public void answer_with_callback(){
- //使用Answer来生成我们我们期望的返回
- when(mockList.get(anyInt())).thenAnswer(new Answer<Object>() {
- @Override
- public Object answer(InvocationOnMock invocation) throws Throwable {
- Object[] args = invocation.getArguments();
- return "hello world:"+args[0];
- }
- });
- assertEquals("hello world:0",mockList.get(0));
- assertEquals("hello world:999",mockList.get(999));
- }
12、监控真实对象
使用spy来监控真实的对象,需要注意的是此时我们需要谨慎的使用when-then语句,而改用do-when语句
- @Test(expected = IndexOutOfBoundsException.class)
- public void spy_on_real_objects(){
- List list = new LinkedList();
- List spy = spy(list);
- //下面预设的spy.get(0)会报错,因为会调用真实对象的get(0),所以会抛出越界异常
- //when(spy.get(0)).thenReturn(3);
- //使用doReturn-when可以避免when-thenReturn调用真实对象api
- doReturn(999).when(spy).get(999);
- //预设size()期望值
- when(spy.size()).thenReturn(100);
- //调用真实对象的api
- spy.add(1);
- spy.add(2);
- assertEquals(100,spy.size());
- assertEquals(1,spy.get(0));
- assertEquals(2,spy.get(1));
- verify(spy).add(1);
- verify(spy).add(2);
- assertEquals(999,spy.get(999));
- spy.get(2);
- }
13、修改对未预设的调用返回默认期望值
- @Test
- public void unstubbed_invocations(){
- //mock对象使用Answer来对未预设的调用返回默认期望值
- List mock = mock(List.class,new Answer() {
- @Override
- public Object answer(InvocationOnMock invocation) throws Throwable {
- return 999;
- }
- });
- //下面的get(1)没有预设,通常情况下会返回NULL,但是使用了Answer改变了默认期望值
- assertEquals(999, mock.get(1));
- //下面的size()没有预设,通常情况下会返回0,但是使用了Answer改变了默认期望值
- assertEquals(999,mock.size());
- }
14、捕获参数来进一步断言
- @Test
- public void capturing_args(){
- PersonDao personDao = mock(PersonDao.class);
- PersonService personService = new PersonService(personDao);
- ArgumentCaptor<Person> argument = ArgumentCaptor.forClass(Person.class);
- personService.update(1,"jack");
- verify(personDao).update(argument.capture());
- assertEquals(1,argument.getValue().getId());
- assertEquals("jack",argument.getValue().getName());
- }
- class Person{
- private int id;
- private String name;
- Person(int id, String name) {
- this.id = id;
- this.name = name;
- }
- public int getId() {
- return id;
- }
- public String getName() {
- return name;
- }
- }
- interface PersonDao{
- public void update(Person person);
- }
- class PersonService{
- private PersonDao personDao;
- PersonService(PersonDao personDao) {
- this.personDao = personDao;
- }
- public void update(int id,String name){
- personDao.update(new Person(id,name));
- }
- }
15、真实的部分mock
- @Test
- public void real_partial_mock(){
- //通过spy来调用真实的api
- List list = spy(new ArrayList());
- assertEquals(0,list.size());
- A a = mock(A.class);
- //通过thenCallRealMethod来调用真实的api
- when(a.doSomething(anyInt())).thenCallRealMethod();
- assertEquals(999,a.doSomething(999));
- }
- class A{
- public int doSomething(int i){
- return i;
- }
- }
16、重置mock
-
- @Test
- public void reset_mock(){
- List list = mock(List.class);
- when(list.size()).thenReturn(10);
- list.add(1);
- assertEquals(10,list.size());
- //重置mock,清除所有的互动和预设
- reset(list);
- assertEquals(0,list.size());
- }