mockito使用入门,一个简单案例足以说明

先看我的controller

@Controller
public class UserController {
    private UserDao userDao;

    public UserController(UserDao userDao) {
        this.userDao = userDao;
    }

    @RequestMapping("/login")
    public String login(HttpServletRequest request) throws Exception {
        String name = request.getParameter("name");
        String password = request.getParameter("password");
        if (userDao.exist(name, password)) {
            return "index";
        } else {
            return "login";
        }
    }

很简单,就假如我想要去对login这个方法进行下单元测试.
假如此时我的dao是不可用的,调用直接抛出异常:

并且HttpServletRequest对象也是要项目运行才有的:
那么现在测试controller这个方法就要依赖于dao和httpServletRequest两个对象.而我只是想测试一下controller的login方法内部的逻辑而已有什么办法能够减少这种依赖关系,从而把重点放在login内部逻辑上的测试么?
那么mockito就是专门用来干这种事情的:

依赖

<dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-all</artifactId>
            <version>1.10.19</version>
            <scope>test</scope>
        </dependency>

测试类:

package van.unittest.test.controller;

import org.junit.Before;
import org.junit.Test;
import org.junit.jupiter.api.BeforeEach;
import org.junit.runner.RunWith;
import org.mockito.Mockito;
import org.mockito.junit.MockitoJUnitRunner;
import van.unittest.test.dao.UserDao;

import javax.servlet.http.HttpServletRequest;

import static org.junit.jupiter.api.Assertions.*;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.ArgumentMatchers.anyString;
import static org.mockito.Mockito.when;
@RunWith(MockitoJUnitRunner.class)
public class UserControllerTest {
    private UserDao userDao;
    private UserController userController;
    private HttpServletRequest request;

    @Before
   public void setUp() {
        this.userDao= Mockito.mock(UserDao.class);
        this.userController=new UserController(userDao);
        this.request=Mockito.mock(HttpServletRequest.class);
    }
    @Test
    public void testLoginSuccess() throws Exception {
    when(request.getParameter("name")).thenReturn("van");
    when(request.getParameter("password")).thenReturn("123");
    when(userDao.exist(anyString(),anyString())).thenReturn(true);
    assert(userController.login(request)).equals("login");
    }

}

这就是去mock行为

这样就能够把重心放在login方法内部了.

answer用法:

package van.unittest.test.mockAction;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mockito;
import org.mockito.junit.MockitoJUnitRunner;

import java.util.List;

import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.Mockito.when;

/**
 * answer用于mock一个更为复杂的行为
 */
@RunWith(MockitoJUnitRunner.class)
public class Answer {
    private List list;
    @Before
    public void setUp(){
        this.list= Mockito.mock(List.class);
    }
    //mock一个更复杂的行为
    @Test
    public void answer(){
        when(list.get(anyInt())).thenAnswer(invocationOnMock -> {
            Integer param=invocationOnMock.getArgument(0,Integer.class);
            return String.valueOf(param*10);
        });
        System.out.println(list.get(1));
    }
}