Mockito框架入门教程（二）
接上一篇，继续学习其它的....
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，使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());
}
