springboot 结合JUnit 构建单元测试

1. 引入spring-boot-starter-test ,相关jar包，如果此依赖中有排除JUnit的exclusions，需要先注销掉，引入JUnit相关依赖：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
    <!--<exclusions>
        <exclusion>
            <groupId>org.junit.vintage</groupId>
            <artifactId>junit-vintage-engine</artifactId>
        </exclusion>
    </exclusions>-->
</dependency>

2. Springboot 会在跟main同级的目录下创建test目录，包含*ApplicationTests这样的一个测试类示例：

package com.jianxin.api;

import com.jianxin.api.service.PurchaseService;
import com.jianxin.fan.entity.Product;
import org.junit.Assert;
import org.junit.jupiter.api.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 tk.mybatis.spring.annotation.MapperScan;

@RunWith(SpringRunner.class)
@MapperScan("com.jianxin.fan.mapper")
@SpringBootTest
class ApiApplicationTests {

    @Autowired
    private PurchaseService purchaseService;

    @Test
    void contextLoads() {
        Product product = purchaseService.getProduct(1);
        // 判断产品信息是否为空
        Assert.assertNotNull(product);

        boolean b=purchaseService.purchase(1,1,3);
        // 判断返回是否为true
        Assert.assertTrue(b);
    }

}

3. contextLoads刚开始是一个空逻辑，其中注解@RunWith所载入类SpringRunner是spring结合JUnit的运行器，所以这里可以进行JUnit测试。@SpringBootTest是可以配置Spring boot的关于测试的相关功能。
4. 加入业务逻辑代码 ：

@Autowired
private PurchaseService purchaseService;

5. 使用Assert.assert…()方法进行结果的判断，在该类上，右键run或debug运行，即可进行单元测试，如果涉及到数据库mapper的操作，需要使用@MapperScan(“com.jianxin.fan.mapper”)，与ApiApplication（@SpringBootApplication）保持一致。
6. 运行后如果有报错，说明测试没通过，如果没有报错，则测试通过。
7. 有时候，本机已经启动了8080端口，这时进行测试会占用这个端口，为了克服这个问题，在Spring Boot中提供了随机端口的机制，并且可以使用REST风格进行测试。
8. 使用随机端口启动测试服务，修改注解@SpringBootTest为：

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)

9. REST风格可以使用TestRestTemplate模板，进行：

package com.jianxin.web;

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.web.client.TestRestTemplate;

//@SpringBootTest
//可以使用随机端口启动测试服务
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class WebApplicationTests {

    // REST测试模板，Springboot自动提供
    @Autowired
    private TestRestTemplate restTemplate;

    @Test
    void contextLoads() {
    }

    @Test
    public void testPurchase(){
        boolean b=this.restTemplate.getForObject("/purchase/purchase",Boolean.class,1,1,4);
    }

}

11. 如果遇到报错：

Test ignored.

java.lang.IllegalStateException: Found multiple @SpringBootConfiguration annotated classes [Generic bean: class [com.jianxin.WebApplication]; scope=; abstract=false; lazyInit=null; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null; defined in file [E:\xjst\个人\技术落地文档\学习练习项目\20200804\high-concurrent-maven-learn\hcml-web\target\classes\com\jianxin\WebApplication.class], Generic bean: class [com.jianxin.ApiApplication]; scope=; abstract=false; lazyInit=null; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null; defined in file [E:\xjst\个人\技术落地文档\学习练习项目\20200804\high-concurrent-maven-learn\hcml-api\target\classes\com\jianxin\ApiApplication.class]]

有可能是因为依赖的jar包（或依赖的maven其他子模块）中有springboot启动类，junit不知道加载哪个启动类，需要注解@SpringBootApplication或@SpringBootTest注解
12. 测试过程中，如果在项目中加入了spring security ，并且没有重写相关方法，需要将security注销掉，或重写security相关的验证方法，否则测试controller相关接口时，可能返回401 UNAUTHORIZED：

2020-08-07 15:30:46.065 DEBUG 10216 --- [           main] o.s.web.client.RestTemplate              : HTTP GET http://localhost:50956/hcmlweb/purchase/purchase
2020-08-07 15:30:46.117 DEBUG 10216 --- [           main] o.s.web.client.RestTemplate              : Accept=[application/json, application/*+json]
2020-08-07 15:30:46.199  INFO 10216 --- [o-auto-1-exec-1] o.a.c.c.C.[.[localhost].[/hcmlweb]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2020-08-07 15:30:46.199  INFO 10216 --- [o-auto-1-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2020-08-07 15:30:46.199 DEBUG 10216 --- [o-auto-1-exec-1] o.s.web.servlet.DispatcherServlet        : Detected StandardServletMultipartResolver
2020-08-07 15:30:46.217 DEBUG 10216 --- [o-auto-1-exec-1] o.s.web.servlet.DispatcherServlet        : enableLoggingRequestDetails='false': request parameters and headers will be masked to prevent unsafe logging of potentially sensitive data
2020-08-07 15:30:46.218  INFO 10216 --- [o-auto-1-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 19 ms
2020-08-07 15:30:46.262 DEBUG 10216 --- [o-auto-1-exec-1] o.s.web.servlet.DispatcherServlet        : "ERROR" dispatch for GET "/hcmlweb/error", parameters={}
2020-08-07 15:30:46.266 DEBUG 10216 --- [o-auto-1-exec-1] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController#error(HttpServletRequest)
2020-08-07 15:30:46.297 DEBUG 10216 --- [o-auto-1-exec-1] o.s.w.s.m.m.a.HttpEntityMethodProcessor  : Using 'application/json', given [application/json, application/*+json] and supported [application/json, application/*+json, application/json, application/*+json]
2020-08-07 15:30:46.298 DEBUG 10216 --- [o-auto-1-exec-1] o.s.w.s.m.m.a.HttpEntityMethodProcessor  : Writing [{timestamp=Fri Aug 07 15:30:46 CST 2020, status=401, error=Unauthorized, message=, path=/hcmlweb/pur (truncated)...]
2020-08-07 15:30:46.322 DEBUG 10216 --- [o-auto-1-exec-1] o.s.web.servlet.DispatcherServlet        : Exiting from "ERROR" dispatch, status 401
2020-08-07 15:30:46.327 DEBUG 10216 --- [           main] o.s.web.client.RestTemplate              : Response 401 UNAUTHORIZED
2020-08-07 15:30:46.328 DEBUG 10216 --- [           main] o.s.web.client.RestTemplate              : Reading to [com.jianxin.web.util.Result]