[SpringBoot] Use Junit for code testing

Junit is a well-known Java testing framework. By integrating Junit + SpringBoot Test, you can use SpringBoot’s dependency injection and other SpringBoot features in Test programs.

Rely on

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
</dependency>
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <scope>test</scope>
</dependency>
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The test Service

Location: SRC/main/Java/com/example/service/impl HelloServiceImpl. Java

package com.example.service.impl;

@Service
public class HelloServiceImpl implements HelloService {

    @Override
    public String helloTo(String name) {
        // Write a Bug on purpose
        if ("C++".equals(name))
            return "Don't hello to C++";
        return StringUtils.hasText(name) ? "HELLO " + name : "HELLO WORLD"; }}Copy the code

To test this code, Java’s general way is to create the required resources and test them, but then you can’t use SpringBoot’s various features. If there are too many dependencies, or there are too many configurations to read, it’s a nightmare:

private HelloService helloService;

@Before
public void setUp(a) {
    helloService = new HelloService();
}

@Test
public void helloTo(a) {
    assertEquals("HELLO WORLD", helloService.helloTo(""));
    assertEquals("HELLO WORLD", helloService.helloTo("WORLD"));
    assertEquals("HELLO JAVA", helloService.helloTo("JAVA"));
    assertEquals("HELLO C++", helloService.helloTo("C++")); / / error
}
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Method 1: Annotate SpringBoot

Location: the SRC/test/Java/com/example/service/impl HelloServiceImplTest. Java

Key points:

• Using the Junit SpringBoot Test framework:@RunWith(SpringRunner.class)
• Specify startup entry:@springboottest (classes = [SpringBoot program entry class])

At the end of the test, the SpringBoot context is automatically closed.

package com.example.service.impl;

import com.example.SpringBootTestApplication;
import com.example.service.HelloService;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import static org.junit.Assert.*;

@RunWith(SpringRunner.class)
@SpringBootTest(classes = SpringBootTestApplication.class)
public class HelloServiceImplTest {

    @Autowired
    private HelloService helloService;

    @Test
    public void helloTo(a) {
        assertEquals("HELLO WORLD", helloService.helloTo(""));
        assertEquals("HELLO WORLD", helloService.helloTo("WORLD"));
        assertEquals("HELLO JAVA", helloService.helloTo("JAVA"));
        assertEquals("HELLO C++", helloService.helloTo("C++")); / / error}}Copy the code

Method 2: Explicitly start SpringBoot

It is also possible to use all of SpringBoot’s features to test by starting the SpringBoot program with the SpringApplication:: Run method, but it is a little more difficult. And SpringBootContext must be closed manually after the test.

package com.example.service.impl;

import com.example.SpringBootTestApplication;
import com.example.service.HelloService;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.springframework.boot.SpringApplication;
import org.springframework.context.ConfigurableApplicationContext;

import static org.junit.Assert.assertEquals;

public class HelloServiceImplTest2 {

    private ConfigurableApplicationContext context;
    private HelloService helloService;

    @Before
    public void setUp(a) {
        context = SpringApplication.run(SpringBootTestApplication.class);
        // Get beans explicitly, depending on SpringBoot to inject them automatically
        helloService = context.getBean(HelloService.class);
    }

    @After
    public void tearDown(a) {
        // Close the SpringBoot program
        context.close();
    }

    @Test
    public void helloTo(a) {
        assertEquals("HELLO WORLD", helloService.helloTo(""));
        assertEquals("HELLO WORLD", helloService.helloTo("WORLD"));
        assertEquals("HELLO JAVA", helloService.helloTo("JAVA"));
        assertEquals("HELLO C++", helloService.helloTo("C++")); / / error}}Copy the code