Spring Boot unit testing quick start Demo

3 min readApr 4, 2024

1.test introduction

Software testing is a guarantee of application software quality. Developers developing interfaces often ignore interface unit testing. If you know how to mock unit tests, your number of bugs will be greatly reduced. Spring provides test module. Overall, the test types supported by Spring Boot Test can be roughly divided into the following three categories:

Unit testing: Generally method-oriented, when writing general business code, the testing cost is relatively high. The annotations involved are @Test.
Slice testing: Generally oriented to boundary functions that are difficult to test, between unit testing and functional testing. The annotations involved include @RunWith @WebMvcTest, etc.
Functional testing: Generally oriented to a complete business function, you can also use the mocking capability in aspect testing, which is recommended. The annotations involved include @RunWith @SpringBootTest, etc.

Several key elements and support methods in the functional testing process are as follows:

Test running environment: start the spring container through @RunWith and @SpringBootTest.
Mock capability: Mockito provides powerful mock function.
Assertion capabilities: AssertJ, Hamcrest, and JsonPath provide powerful assertion capabilities.

2.Code Project

Experiment purpose: verify controller and service layer logicpom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springboot-demo</artifactId>
        <groupId>com.et</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>test</artifactId>
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-autoconfigure</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

configurations

server:
  port: 8088
  username: default

server:
  port: 8088
  username: dev

cotroller

package com.et.test.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import java.util.HashMap;
import java.util.Map;
@Controller
public class HelloWorldController {
    @RequestMapping("/hello")
    @ResponseBody
    public Map<String, Object> showHelloWorld(){
        Map<String, Object> map = new HashMap<>();
        map.put("msg", "HelloWorld");
        return map;
    }
}

service

package com.et.test.service;
import org.springframework.stereotype.Service;
/**
 * @ClassName UserService
 * @Description TODO
 * @Author liuhaihua
 * @Date 2024/4/4 13:13
 * @Version 1.0
 */
public interface UserService {
   public   String getUserName();
}

package com.et.test.service;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
/**
 * @ClassName UserServiceImpl
 * @Description TODO
 * @Author liuhaihua
 * @Date 2024/4/4 13:16
 * @Version 1.0
 */
@Service
public class UserServiceImpl implements UserService{
   @Value("${server.username}")
   private String username;
   @Override
   public String getUserName() {
      return username;
   }
}

DemoApplication.java

package com.et.test;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class DemoApplication {
   public static void main(String[] args) {
      SpringApplication.run(DemoApplication.class, args);
   }
}

The above are just some key codes. For all codes, please see the code repository below.

Code Repository

https://github.com/Harries/springboot-demo

3.Test

Verify environment binding

@ActiveProfiles("dev")

You can switch to different environments and test in the same environment

Verify controller

@Test
public void bookApiTest() throws Exception {
// mockbean start
   userServiceMockBean();
   // mockbean end
   String expect = "{\"msg\":\"HelloWorld\"}";
   mockMvc.perform(MockMvcRequestBuilders.get("/hello"))
         .andExpect(MockMvcResultMatchers.content().json(expect))
         .andDo(MockMvcResultHandlers.print());
   // mockbean reset
}

Verify service

@Test
  public void execute() {
      userServiceMockBean();
      log.info("username:"+userService.getUserName());
      Assertions.assertThat(userService.getUserName().equals("mockname"));
}

The following is the complete test code. If you are interested, you can test it.

package com.et.test;
import com.et.test.service.UserService;
import org.assertj.core.api.Assertions;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.BDDMockito;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.mock.mockito.MockBean;
import org.springframework.test.context.ActiveProfiles;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import org.springframework.test.web.servlet.result.MockMvcResultHandlers;
import org.springframework.test.web.servlet.result.MockMvcResultMatchers;
import javax.annotation.Resource;

@RunWith(SpringRunner.class)
@SpringBootTest(classes = DemoApplication.class)
@ActiveProfiles("dev")
@AutoConfigureMockMvc
public class DemoTests {
    private Logger log = LoggerFactory.getLogger(getClass());
   @Resource
   private MockMvc mockMvc;
   //@Autowired
   @MockBean
   UserService userService;
    @Before
    public void before()  {
        log.info("init some data");
    }
    @After
    public void after(){
        log.info("clean some data");
    }
    @Test
    public void execute() {
      userServiceMockBean();
        log.info("username:"+userService.getUserName());
      Assertions.assertThat(userService.getUserName().equals("mockname"));
    }
   @Test
   public void bookApiTest() throws Exception {
      // mockbean start
      userServiceMockBean();
      // mockbean end
      String expect = "{\"msg\":\"HelloWorld\"}";
      mockMvc.perform(MockMvcRequestBuilders.get("/hello"))
            .andExpect(MockMvcResultMatchers.content().json(expect))
            .andDo(MockMvcResultHandlers.print());
      // mockbean reset
   }
   public void userServiceMockBean() {
      BDDMockito.given(userService.getUserName()).willReturn("mockname");
   }
}