javax.validation.ValidationException : HV000028: Unexpected exception during isValid in Test

Question

我不知道如何为自定义约束 validator 编写单元测试。我有以下 validator 类:

@Slf4j
@AllArgsConstructor
@NoArgsConstructor
public class SchoolIdValidator implements ConstraintValidator<ValidSchoolId, String> {

    private SchoolService schoolService;

    @Override
    public void initialize(ValidSchoolId constraintAnnotation) {}

    @Override
    public boolean isValid(String s, ConstraintValidatorContext constraintValidatorContext) {
        return schoolService.isValidSchoolId(s);
    }
}

validator 由以下注释使用:

@Target({ElementType.METHOD, ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = SchoolIdValidator.class)
public @interface ValidSchoolId {

    String message() default "Must be a valid school. Found: ${validatedValue}";
    Class<?>[] groups() default {};
    Class<? extends Payload>[] payload() default {};

}

SchoolService 是一个使用 ApiClient 调用 School Api 的类，ApiClient 是一个具有通用 RestTemplate 请求的通用类:

@Service
@AllArgsConstructor
public class SchoolService {

    private ApiClient apiSchoolClient;

    public Boolean isValidSchoolId(String schoolId){
        try {
            ResponseEntity res = apiSchoolClient.get(
                    String.format("/stores/%s", schoolId), Object.class, null);
            return res.getStatusCode().is2xxSuccessful();
        } catch (HttpClientErrorException e) {
            if(e.getStatusCode().value() == 404)
                return false;
            else
                throw new TechnicalException("Can't get response from school Api");
        } catch(RestClientException e) {
            throw new TechnicalException("Can't get response from School Api");
        }
    }
}

最后是学生类:

@Data
public class Student {

    private String id;
    private String firstName;
    private String lastName;
    @ValidSchoolId
    private String schoolId;
}

当我运行该应用程序时，它运行良好。但是，它根本不适用于以下测试类:

@RunWith(MockitoJUnitRunner.class)
@ExtendWith(SpringExtension.class)
public class SchoolIdValidatorTest {

    Validator validator;

    @InjectMocks
    private SchoolService schoolService;

    @Mock
    private ApiClient apiSchoolClient;

    @Before
    public void setUp() throws Exception {
        validator = Validation.buildDefaultValidatorFactory().getValidator();
        MockitoAnnotations.initMocks(this);
    }


    @Test
    public void isValid_SchoolIdExists_ShouldValidate() {

        Mockito.when(this.apiSchoolClient.get(Mockito.eq("/schools/12"), Mockito.any(), Mockito.any()))
                .thenReturn(new ResponseEntity<>(HttpStatus.OK));
        //given
        Student student = new Student();
        simulation.setSchoolId("12");
        //when
        Set<ConstraintViolation<Student>> violations = validator.validate(student);

        //then
        assertEquals(0, violations.size());
    }

当它出现在 SchoolIdValidator 中时，schoolService 始终为 null。因此，它总是在 SchoolIdValidator.isValid 上抛出 NPE。如果有人有解决方案，那将非常有帮助。

感谢您的阅读和帮助。

Answer 1

这里的@InjectMocks可能就是问题所在。

@RunWith(MockitoJUnitRunner.class)
@ExtendWith(SpringExtension.class)
public class SchoolIdValidatorTest {

    Validator validator;

    @InjectMocks
    private SchoolService schoolService;

连同

Validation.buildDefaultValidatorFactory().getValidator()

我假设 SchoolService 通常是一个 Spring 托管 bean，并且 SchoolIdValidator 会将其注入(inject)。通过使用 @InjectMocks ，您可以说这不是 Spring 托管 bean。此类由 Mockito 实例化，因此它永远不会被注入(inject)到您的 validator 中。

我不确定这里的正确解决方案是什么，因为您没有发布任何配置类。最有可能的是，您需要一个额外的测试配置类来实例化您的 validator ApiClient 并注入(inject)您的 SchoolService。您还可以使用 @MockBean 模拟 ApiClient，这将使其成为 Spring 托管 bean，但也允许模拟。

有点相关，这里确实有构造函数。没有理由使用@InjectMocks。只需使用 new SchoolService(apiSchoolClient) 即可。