概述
官网： http://mockito.org
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>import static org.mockito.Mockito.*;
import static org.junit.Assert.*;下面我们开始使用mockito来做测试
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"));
} @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;
}
} @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");
} @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>}
@Test(expected = RuntimeException.class)
public void doThrow_when(){
List list = mock(List.class);
doThrow(new RuntimeException()).when(list).add(1);
list.add(1);
} @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");
} @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);
} @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);
}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; @Test
public void shorthand(){
mockList.add(1);
verify(mockList).add(1);
}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);
}
@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));
}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);
}
@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());
}
@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));
}
}
@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;
}
}
@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());
}最后
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