如何在嵌套MapStruct Mapper中Mock Service A？

问题场景 #

测试AnnouncementMapper时，该Mapper通过MapStruct的@Mapper(uses = ForwardMapper.class)引入了ForwardMapper，而ForwardMapper内部依赖ServiceA。尝试MockServiceA的isEnabled方法返回true，但发现ForwardMapper中的ServiceA并非Mock实例，导致Mock逻辑完全不生效。

相关代码 #

原AnnouncementMapper代码 #

@Mapper(uses = {
        ForwardMapper.class // 内部依赖ServiceA
},
        builder = @Builder(disableBuilder = true),
        componentModel = "spring"
)
public interface AnnouncementMapper {

    @Mapping(source = ".", target = "carrier")
    // 其他映射方法...
    @Mapping(source = ".", target = "forward", qualifiedByName = "ForwardMapper")
    Schedule mapForSchedule(Announcement announcement);
}

原测试代码 #

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.NONE)
@AutoConfigureObservability(tracing = false)
class Mapper extends Specification {

    private AService serviceA = Mock()

    @Autowired
    Mapper mapper

    def "map announcement to some other announcement"() {
        given:
        1 * ServiceA.isEnabled(Value.A) >> true

        when:
        def result = mapper.map(announcement)
        // 后续逻辑...
    }
}

注：ForwardMapper是注入了ServiceA的Spring Bean。

问题原因 #

原测试中仅手动创建了ServiceA的Mock实例，但该实例并未被Spring容器管理，也未注入到ForwardMapper中。ForwardMapper仍使用Spring上下文初始化的原生ServiceA实例，因此Mock的交互逻辑无法触发。

解决方案 #

方案一：使用@MockBean替换Spring容器中的ServiceA #

通过Spring Boot的@MockBean注解，将Mock的ServiceA实例替换Spring容器中原有的实例，所有依赖ServiceA的Bean（包括ForwardMapper）都会自动注入该Mock实例。

修改后的测试代码：

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.NONE)
@AutoConfigureObservability(tracing = false)
class AnnouncementMapperSpec extends Specification {

    @MockBean
    AService serviceA

    @Autowired
    AnnouncementMapper mapper

    def "map announcement to schedule"() {
        given:
        1 * serviceA.isEnabled(Value.A) >> true
        // 初始化测试用的Announcement对象
        def announcement = new Announcement()
        // 设置announcement的必要属性...

        when:
        Schedule result = mapper.mapForSchedule(announcement)

        then:
        // 验证forward字段的映射结果符合预期
        result.getForward() != null
        // 其他验证逻辑...
    }
}

方案二：手动将Mock的ServiceA注入到ForwardMapper #

如果不想使用@MockBean（比如希望减少Spring上下文加载开销），可以手动获取ForwardMapper实例，并将Mock的ServiceA注入进去。需要确保ForwardMapper提供了ServiceA的setter方法，或通过反射完成注入。

修改后的测试代码：

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.NONE)
@AutoConfigureObservability(tracing = false)
class AnnouncementMapperSpec extends Specification {

    private AService serviceA = Mock()

    @Autowired
    AnnouncementMapper mapper

    @Autowired
    ForwardMapper forwardMapper

    def setup() {
        // 方式1：若ForwardMapper有setter方法
        forwardMapper.setServiceA(serviceA)

        // 方式2：无setter时用反射注入
        // def serviceField = ForwardMapper.getDeclaredField("serviceA")
        // serviceField.setAccessible(true)
        // serviceField.set(forwardMapper, serviceA)
    }

    def "map announcement to schedule"() {
        given:
        1 * serviceA.isEnabled(Value.A) >> true
        def announcement = new Announcement()
        // 设置属性...

        when:
        Schedule result = mapper.mapForSchedule(announcement)

        then:
        // 验证逻辑...
    }
}

内容的提问来源于stack exchange，提问作者Matexon