Spring Boot 3.0中ObservationRegistry的JUnit测试是否有替代实现方案？

背景 #

在Spring Boot 3.0环境下，针对控制器中使用Observation的/getAllRecommendedMovies接口，已编写了基于静态Mock的JUnit测试，现探讨其他更优雅的替代测试方案。

现有代码 #

控制器中的GET方法 #

@GetMapping("/getAllRecommendedMovies")
public ResponseEntity<BookMyTicket> getAllRecommendedMovies(
  @RequestParam(value = "theatreName", required = false) String theatreName,
  @RequestParam(value = "pincode", required = false) Integer pincode,
  HttpServletRequest request) {

  return Observation.createNotStarted(
    request.getRequestURI().substring(1),
    observationRegistry
  ).observe(() -> new ResponseEntity<>(
    theatreManagementService.getAllRecommendedMovies(theatreName, pincode),
    HttpStatus.OK
  ));
}

现有JUnit测试代码 #

@Test
public void getAllRecommendedMovies() throws Exception {
  try (MockedStatic<Observation> utilities = Mockito.mockStatic(Observation.class)) {
    utilities.when(
      () -> Observation.createNotStarted(Mockito.eq("getAllRecommendedMovies"), Mockito.any())
    ).thenReturn(Observation.NOOP);
  }
  mockMvc.perform(get("/getAllRecommendedMovies")).andExpect(status().isOk());
}

替代测试方案 #

方案1：注入No-op类型的ObservationRegistry #

通过向测试环境注入无操作（No-op）的ObservationRegistry，避免静态Mock，更贴合Spring依赖注入的设计理念。

测试代码示例：

@Autowired
private MockMvc mockMvc;

@Autowired
private ObservationRegistry observationRegistry;

@BeforeEach
void setUp() {
    // 配置ObservationRegistry使用无操作处理器
    observationRegistry.observationConfig().observationHandler(new NoOpObservationHandler());
}

@Test
public void getAllRecommendedMovies() throws Exception {
    mockMvc.perform(get("/getAllRecommendedMovies"))
           .andExpect(status().isOk());
}

也可以直接在测试类中提供No-op的ObservationRegistry Bean：

@Configuration
static class TestConfig {
    @Bean
    public ObservationRegistry observationRegistry() {
        return ObservationRegistry.noOp();
    }
}

方案2：重构代码抽离Observation创建逻辑 #

将Observation的创建逻辑封装到独立组件中，测试时Mock该组件而非静态方法，提升代码可测试性。

步骤1：创建Observation辅助组件

@Component
public class ObservationHelper {
    private final ObservationRegistry observationRegistry;

    public ObservationHelper(ObservationRegistry observationRegistry) {
        this.observationRegistry = observationRegistry;
    }

    public Observation createObservation(String name) {
        return Observation.createNotStarted(name, observationRegistry);
    }
}

步骤2：修改控制器注入辅助组件

@Autowired
private ObservationHelper observationHelper;

@GetMapping("/getAllRecommendedMovies")
public ResponseEntity<BookMyTicket> getAllRecommendedMovies(
  @RequestParam(value = "theatreName", required = false) String theatreName,
  @RequestParam(value = "pincode", required = false) Integer pincode,
  HttpServletRequest request) {

  return observationHelper.createObservation(request.getRequestURI().substring(1))
                          .observe(() -> new ResponseEntity<>(
                            theatreManagementService.getAllRecommendedMovies(theatreName, pincode),
                            HttpStatus.OK
                          ));
}

步骤3：编写测试Mock辅助组件

@Autowired
private MockMvc mockMvc;

@MockBean
private ObservationHelper observationHelper;

@Test
public void getAllRecommendedMovies() throws Exception {
    when(observationHelper.createObservation("getAllRecommendedMovies"))
        .thenReturn(Observation.NOOP);
    
    mockMvc.perform(get("/getAllRecommendedMovies"))
           .andExpect(status().isOk());
}

方案3：利用Spring Boot Test的观测自动配置 #

Spring Boot Test提供@AutoConfigureObservations注解，可简化测试环境下的观测配置，无需手动Mock静态方法或组件。

测试代码示例：

@SpringBootTest
@AutoConfigureMockMvc
@AutoConfigureObservations
public class TheatreManagementControllerTest {

    @Autowired
    private MockMvc mockMvc;

    @Test
    public void getAllRecommendedMovies() throws Exception {
        mockMvc.perform(get("/getAllRecommendedMovies"))
               .andExpect(status().isOk());
    }
}

该注解会自动配置测试用的Observation环境，默认不产生实际观测数据，适合单元测试场景。

内容的提问来源于stack exchange，提问作者Joseph24x7