Junit

brief introduction （from baidu）

JUnit It's a Java The language's unit testing framework . It consists of Kent Beck and Erich Gamma establish , Gradually become from Kent Beck Of sUnit Of xUnit The most successful one in the family . JUnit It has its own JUnit Expand the ecosystem . Most of the Java The development environment of has been integrated JUnit As a tool for unit testing

JUnit By Erich Gamma and Kent Beck Write a regression testing framework （regression testing framework）.Junit Testing is programmer testing , The so-called white box test , Because programmers know how the software being tested （How） How to complete the function and what to complete （What） The function of .Junit It's a framework , Inherit TestCase class , You can use it Junit It's automated

Junit5 Can't use @RunWith

If you used the previous Spring In the version, everyone is doing junit Unit tests will be used @RunWith Appoint Spring Kernel testing , however Spring5 After use junit There is no such annotation

reason

It's actually Spring Support Junit5, stay 5 There is no such annotation in. It has been integrated, so it doesn't need to be used anymore @RunWith（）
@RunWith The functions of are @ExtendWith replace , The original @RunWith(SpringRunner.class) By the same function @ExtendWith(SpringExtension.class) replace . but JUnit5 in @SpringBootTest The annotation already contains... By default @ExtendWith(SpringExtension.class).

So Spring Can only be used in Spring4

Because the version corresponds to @ExtendWith(SpringJUnit4ClassRunner.class)
I won't write code for you here
See my article on unit testing :SpringBoot—— unit testing
But if you reduce the version to use Junit4 To test, I give the following simple example

package com.exampl.junitTest;

import com.exampl.configuration.TestConfiguation;
import com.exampl.service.TestService;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;



// Specifies the kernel to use 
@RunWith(SpringJUnit4ClassRunner.class)
//@ExtendWith(SpringJUnit4ClassRunner.class)
// Indicates the configuration context 
@ContextConfiguration(classes = {
    TestConfiguation.class})
public class TestBetter {
    

    // Automatic injection 
    @Autowired
    private TestService testService;

    @Test
    public void testServiceTest(){
    
      this.testService.testShow();
    }
}