美文网首页
mockito简单教程

mockito简单教程

作者: 金融测试民工 | 来源:发表于2020-06-07 16:31 被阅读0次

    (最近学习Mock,看到一些好的文章分享一下)

    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

    一、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>

    二、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.*;

    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"));

    }

    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{

    @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);

    }

    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() {

    @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 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());

    }

    相关文章

      网友评论

          本文标题:mockito简单教程

          本文链接:https://www.haomeiwen.com/subject/wbvctktx.html