简介
Spring Boot 2.2.0 版本开始引入 JUnit 5 作为单元测试默认库，在 Spring Boot 2.2.0 版本之前，spring-boot-starter-test 包含了 JUnit 4 的依赖，Spring Boot 2.2.0 版本之后替换成了 Junit Jupiter。
JUnit 4 和 JUnit 5 的差异
1. 忽略测试用例执行
JUnit 4：
@Test @Ignore public void testMethod() { // ... }
JUnit 5：
@Test @Disabled("explanation") public void testMethod() { // ... }
2. RunWith 配置
JUnit 4：
@RunWith(SpringRunner.class) @SpringBootTest public class ApplicationTests { @Test public void contextLoads() { } }
JUnit 5：
@ExtendWith(SpringExtension.class) @SpringBootTest public class ApplicationTests { @Test public void contextLoads() { } }
3. @Before、@BeforeClass、@After、@AfterClass 被替换
- @BeforeEach 替换 @Before
- @BeforeAll 替换 @BeforeClass
- @AfterEach 替换 @After
- @AfterAll 替换 @AfterClass
开发环境
- JDK 8
示例
1.创建 Spring Boot 工程。
2.添加 spring-boot-starter-web 依赖，最终 pom.xml 如下。
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.2.6.RELEASE</version> <relativePath/> </parent> <groupId>tutorial.spring.boot</groupId> <artifactId>spring-boot-junit5</artifactId> <version>0.0.1-SNAPSHOT</version> <name>spring-boot-junit5</name> <description>Demo project for Spring Boot Unit Test with JUnit 5</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <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> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
3.工程创建好之后自动生成了一个测试类。
package tutorial.spring.boot.junit5; import org.junit.jupiter.api.Test; import org.springframework.boot.test.context.SpringBootTest; @SpringBootTest class SpringBootJunit5ApplicationTests { @Test void contextLoads() { } }
这个测试类的作用是检查应用程序上下文是否可正常启动。
@SpringBootTest 注解告诉 Spring Boot 查找带 @SpringBootApplication 注解的主配置类，并使用该类启动 Spring
应用程序上下文。
4.补充待测试应用逻辑代码
4.1. 定义 Service 层接口
package tutorial.spring.boot.junit5.service; public interface HelloService { String hello(String name); }
4.2. 定义 Controller 层
package tutorial.spring.boot.junit5.controller; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RestController; import tutorial.spring.boot.junit5.service.HelloService; @RestController public class HelloController { private final HelloService helloService; public HelloController(HelloService helloService) { this.helloService = helloService; } @GetMapping("/hello/{name}") public String hello(@PathVariable("name") String name) { return helloService.hello(name); } }
4.3. 定义 Service 层实现
package tutorial.spring.boot.junit5.service.impl; import org.springframework.stereotype.Service; import tutorial.spring.boot.junit5.service.HelloService; @Service public class HelloServiceImpl implements HelloService { @Override public String hello(String name) { return "Hello, " + name; } }
5.编写发送 HTTP 请求的单元测试。
package tutorial.spring.boot.junit5; import org.assertj.core.api.Assertions; 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; import org.springframework.boot.web.server.LocalServerPort; @SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT) public class HttpRequestTest { @LocalServerPort private int port; @Autowired private TestRestTemplate restTemplate; @Test public void testHello() { String requestResult = this.restTemplate.getForObject("http://127.0.0.1:" + port + "/hello/spring", String.class); Assertions.assertThat(requestResult).contains("Hello, spring"); } }
说明：
- webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT 使用本地的一个随机端口启动服务；
- @LocalServerPort 相当于 @Value("${local.server.port}")；
- 在配置了 webEnvironment 后，Spring Boot 会自动提供一个 TestRestTemplate 实例，可用于发送 HTTP 请求。
- 除了使用 TestRestTemplate 实例发送 HTTP 请求外，还可以借助 org.springframework.test.web.servlet.MockMvc 完成类似功能，代码如下：
package tutorial.spring.boot.junit5.controller; import org.assertj.core.api.Assertions; import org.junit.jupiter.api.Test; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc; import org.springframework.boot.test.context.SpringBootTest; import org.springframework.test.web.servlet.MockMvc; import org.springframework.test.web.servlet.request.MockMvcRequestBuilders; import org.springframework.test.web.servlet.result.MockMvcResultHandlers; import org.springframework.test.web.servlet.result.MockMvcResultMatchers; @SpringBootTest @AutoConfigureMockMvc public class HelloControllerTest { @Autowired private HelloController helloController; @Autowired private MockMvc mockMvc; @Test public void testNotNull() { Assertions.assertThat(helloController).isNotNull(); } @Test public void testHello() throws Exception { this.mockMvc.perform(MockMvcRequestBuilders.get("/hello/spring")) .andDo(MockMvcResultHandlers.print()) .andExpect(MockMvcResultMatchers.status().isOk()) .andExpect(MockMvcResultMatchers.content().string("Hello, spring")); } }
以上测试方法属于整体测试，即将应用上下文全都启动起来，还有一种分层测试方法，譬如仅测试 Controller 层。
6.分层测试。
package tutorial.spring.boot.junit5.controller; import org.assertj.core.api.Assertions; import org.junit.jupiter.api.Test; import org.mockito.Mockito; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest; import org.springframework.boot.test.mock.mockito.MockBean; import org.springframework.test.web.servlet.MockMvc; import org.springframework.test.web.servlet.request.MockMvcRequestBuilders; import org.springframework.test.web.servlet.result.MockMvcResultHandlers; import org.springframework.test.web.servlet.result.MockMvcResultMatchers; import tutorial.spring.boot.junit5.service.HelloService; @WebMvcTest public class HelloControllerTest { @Autowired private HelloController helloController; @Autowired private MockMvc mockMvc; @MockBean private HelloService helloService; @Test public void testNotNull() { Assertions.assertThat(helloController).isNotNull(); } @Test public void testHello() throws Exception { Mockito.when(helloService.hello(Mockito.anyString())).thenReturn("Mock hello"); this.mockMvc.perform(MockMvcRequestBuilders.get("/hello/spring")) .andDo(MockMvcResultHandlers.print()) .andExpect(MockMvcResultMatchers.status().isOk()) .andExpect(MockMvcResultMatchers.content().string("Mock hello")); } }
说明：
@WebMvcTest 注释告诉 Spring Boot 仅实例化 Controller 层，而不去实例化整体上下文，还可以进一步指定仅实例化 Controller 层的某个实例：@WebMvcTest(HelloController.class)；
因为只实例化了 Controller 层，所以依赖的 Service 层实例需要通过 @MockBean 创建，并通过 Mockito 的方法指定 Mock 出来的 Service 层实例在特定情况下方法调用时的返回结果。
