Springboot创建测试类：

1、导包

<!--测试-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
</dependency>

2、Shift + Alt + T 创建测试类

选择你的包，然后点击OK

3、在测试类上添加注解

@RunWith(SpringRunner.class)
@SpringBootTest(classes = 你的启动类.class)

4、测试

@RunWith(SpringRunner.class)
@SpringBootTest(classes = App.class)
class AnimalMapperTest {
    @Autowired
    private AnimalMapper animalMapper;

    @Test
    public void list(){
        QueryWrapper<Animal> wrapper = new QueryWrapper<>();
        animalMapper.selectList(wrapper).forEach(System.out::println);
    }
}