How to unit test the data access layer in SpringBoot?

foreword

As a TOB enterprise oriented to banks and financial institutions, our company frequently encounters the transformation needs of localized databases proposed by various Party A fathers, including, , and OceanBaseso TiDBon geldenDB. Every adaptation requires a lot of manpower for testing, so is there a more efficient and low-cost way to solve this problem? This article introduces a fast, efficient and reusable solution - unit testing the data access layer.

Mybatis test dependencies

Our project uses SpringBoot+ Mybatisas the development framework, and everyone first thinks that they can use SpringBootthe built-in test annotations @SpringBootTestfor testing. However, one of the biggest disadvantages of using this annotation is that it is necessary to start the entire container and inject all the beans. Then a test is equivalent to starting an application. It takes nearly 70-80 seconds to start our application once, and the day lily is cold .

So is there a better way, is it necessary to inject the full amount of beans? Is it enough to just inject the beans related to the data access layer? In fact, the official mybatishas given us such a solution.

Introduce dependenciesmybatis-spring-boot-starter-test

<dependency>
  <groupId>org.mybatis.spring.boot</groupId>
  <artifactId>mybatis-spring-boot-starter-test</artifactId>
  <version>2.3.0</version>
  <scope>test</scope>
</dependency>

Mapper interface

@Mapper
public interface CityMapper {

    @Select("SELECT * FROM CITY WHERE state = #{state}")
    City findByState(@Param("state") String state);

}

Test class using junit5

// 使用junit5
@MybatisTest
// 使用真实的数据源进行测试
@AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
public class CityMapperTest {

    @Autowired
    private CityMapper cityMapper;

    @Test
    public void findByStateTest() {
        City city = cityMapper.findByState("CA");
        assertThat(city.getName()).isEqualTo("San Francisco");
        assertThat(city.getState()).isEqualTo("CA");
        assertThat(city.getCountry()).isEqualTo("US");
    }

}

Customize a startup class

@MybatisTest By default @SpringBootApplication classes with . Therefore, due to bean some methods defined, some unexpected errors may occur, or some unnecessary components are loaded ApplicationContext . To avoid this, we can create @SpringBootApplicationclasses with a in the same package as the test class.

package sample.mybatis.mapper;

import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
class MapperTestApplication {

}

operation result

For details, refer to github.com/mybatis/spr…

但是， 上面是使用原生mybatis的测试方式，而我们项目用的是基于mybatis封装的开源框架tkMapper，github地址是https://github.com/abel533/Mapper，并不适用啊，无解，只能去看下mybatis-spring-boot-starter-test的原理。