Mockito学习

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PS: Mockito就是为了测试使用

package com.beet.test.yangqiang;


import static org.mockito.Mockito.*;
import static org.junit.Assert.*;

import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import org.junit.Test;
import org.mockito.ArgumentCaptor;
import org.mockito.ArgumentMatcher;
import org.mockito.InOrder;
import org.mockito.exceptions.verification.NoInteractionsWanted;
import org.mockito.invocation.InvocationOnMock;
import org.mockito.stubbing.Answer;

/**
 * Hello world!
 *
 */
public class App 
{
    /*public static void main( String[] args )
    {
        System.out.println( "Hello World!" );
    }*/
    /**
     * 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();
    }
    /**
     * 模拟我们需要的结果
     */
    @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();
    }
    
    /*2.3 RETURNS_SMART_NULLS和RETURNS_DEEP_STUBS*/
    
    @Test
    public void returnsSmartNullsTest() {
         List mock = mock(List.class, RETURNS_SMART_NULLS);
          System.out.println(mock.get(0));
          
          //使用RETURNS_SMART_NULLS参数创建的mock对象，不会抛出NullPointerException异常。另外控制台窗口会提示信息“SmartNull returned by unstubbed get() method on mock”
            System.out.println(mock.toArray().length);  
    }
    
    @Test
    public void deepstubsTest(){
        Account account=mock(Account.class,RETURNS_DEEP_STUBS);
        when(account.getRailwayTicket().getDestination()).thenReturn("Beijing");
        account.getRailwayTicket().getDestination();
        verify(account.getRailwayTicket()).getDestination();
        assertEquals("Beijing",account.getRailwayTicket().getDestination());
    }
    @Test
    public void deepstubsTest2(){
        Account account=mock(Account.class); 
        RailwayTicket railwayTicket=mock(RailwayTicket.class);        
        when(account.getRailwayTicket()).thenReturn(railwayTicket); 
        when(railwayTicket.getDestination()).thenReturn("Beijing");
        
        account.getRailwayTicket().getDestination();
        verify(account.getRailwayTicket()).getDestination();    
        assertEquals("Beijing",account.getRailwayTicket().getDestination());
    }    
    /**
     * 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);
    }
    
    /**
     * 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));
    }
    
    @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 argumentMatchersTest(){
        //创建mock对象
        List<String> mock = mock(List.class);

        //argThat(Matches<T> matcher)方法用来应用自定义的规则，可以传入任何实现Matcher接口的实现类。
        when(mock.addAll(argThat(new IsListofTwoElements()))).thenReturn(true);

        mock.addAll(Arrays.asList("one","two","three"));
        //IsListofTwoElements用来匹配size为2的List，因为例子传入List为三个元素，所以此时将失败。
        verify(mock).addAll(argThat(new IsListofTwoElements()));
    }
    
    @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());
    }
    /**
     * 返回规定的期望结构
     */
    @Test
    public void answerTest(){
        List<String> mockList = mock(List.class);
        when(mockList.get(anyInt())).thenAnswer(new CustomAnswer());
        assertEquals("hello world:0",mockList.get(0));
        assertEquals("hello world:999",mockList.get(999));
    }
    
    @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() {
            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(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 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));
    }
    
    @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());
    }
    
    @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);
    }
    
    @Test(expected = RuntimeException.class)
    public void consecutive_calls(){
          List mockList = mock(List.class);
        //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);//--只有这个有效
        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);
        mockList.get(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);
    }
}
class A{
    public int doSomething(int i){
        return i;
    }
}
class CustomAnswer implements Answer<String>{
    public String answer(InvocationOnMock invocation) throws Throwable {
        Object[] args = invocation.getArguments();
        return "hello world:"+args[0];
    }
}
class IsListofTwoElements extends ArgumentMatcher<List>
{
    public boolean matches(Object list)
    {
        return((List)list).size()==2;
    }
}
class IsValid extends ArgumentMatcher<List>{
    @Override
    public boolean matches(Object o) {
        return o.equals(1)  || o.equals(2);
    }
}

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));
    }
}