测试 MockBean Null

Question

我有这个类定义

@RestController
public class ReservationController {
    @Autowired
    private Reservation reservation;

    @RequestMapping(value = "/reservation", produces = MediaType.APPLICATION_JSON_UTF8_VALUE, method = RequestMethod.POST)
    @ResponseBody
    public Reservation getReservation() {

        return reservation;
    }
}

其中 Reservation 是一个简单的 Pojo

public class Reservation {
    private long id;
    private String reservationName;

    public Reservation() {
        super();
        this.id = 333;
        this.reservationName = "prova123";
    }

    public Reservation(long id, String reservationName) {
        super();
        this.id = id;
        this.reservationName = reservationName;
    }

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getReservationName() {
        return reservationName;
    }

    public void setReservationName(String reservationName) {
        this.reservationName = reservationName;
    }

    @Override
    public String toString() {
        return "Reservation [id=" + id + ", reservationName=" + reservationName + "]";
    }
}

当我尝试测试这个类时

@WebMvcTest
@RunWith(SpringRunner.class)
public class MvcTest {
    @Autowired
    private MockMvc mockMvc;

    @MockBean(name = "reservation")
    private Reservation reservation;

    @Test
    public void postReservation() throws Exception {
        mockMvc.perform(MockMvcRequestBuilders.post("/reservation"))
                .andExpect(MockMvcResultMatchers.content().contentType(MediaType.APPLICATION_JSON_UTF8_VALUE))
                .andExpect(MockMvcResultMatchers.status().isOk());
    }
}

我收到了这个错误：

org.springframework.web.util.NestedServletException：请求处理失败；嵌套异常是 org.springframework.http.converter.HttpMessageConversionException: 类型定义错误：[简单类型，类 org.mockito.internal.debugging.LocationImpl];嵌套异常是 com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No serializer found for class org.mockito.internal.debugging.LocationImpl 并且没有发现创建 BeanSerializer 的属性（为避免异常，禁用 SerializationFeature.FAIL_ON_EMPTY_BEANS）（通过引用链：spring.boot.usingSpringBoot.entity.Reservation$MockitoMock$980801978["mockitoInterceptor"]->org.mockito.internal.creation.bytebuddy.MockMethodInterceptor["mockHandler"]->org.mockito.internal.handler.InvocationNotifierHandler["invocationContainer "]->org.mockito.internal.stubbing.InvocationContainerImpl["invocationForStubbing"]->org.mockito.internal.invocation.InvocationMatcher["invocation"]->org.mockito.internal.invocation.InterceptedInvocation["location"] )

.... ....

原因：com.fasterxml.jackson.databind.exc.InvalidDefinitionException：找不到类 org.mockito.internal.debugging.LocationImpl 的序列化程序，也没有发现创建 BeanSerializer 的属性（为避免异常，请禁用 SerializationFeature.FAIL_ON_EMPTY_BEANS）（通过引用链：spring.boot.usingSpringBoot.entity.Reservation$MockitoMock$980801978["mockitoInterceptor"]->org.mockito.internal.creation.bytebuddy.MockMethodInterceptor["mockHandler"]->org.mockito.internal.handler.InvocationNotifierHandler ["invocationContainer"]->org.mockito.internal.stubbing.InvocationContainerImpl["invocationForStubbing"]->org.mockito.internal.invocation.InvocationMatcher["invocation"]->org.mockito.internal.invocation.InterceptedInvocation["位置"])

如何以正确的方式注入预订？

谢谢

Answer 1

您收到错误是因为当您使用 @MockBean（或在非 Spring 环境中使用 @Mock）时，您会得到一个 Mockito 模拟对象。此对象是您的对象的空心代理。代理具有与您的类相同的公共方法，并且默认返回其返回类型的默认值（例如 null 表示对象，1 表示整数等），或者对 void 方法不执行任何操作.

Jackson 抱怨，因为它必须序列化这个没有字段的代理，而 Jackson 不知道该怎么做。

com.fasterxml.jackson.databind.exc.InvalidDefinitionException: 否 为类 org.mockito.internal.debugging.LocationImpl 找到序列化程序 并且没有发现创建 BeanSerializer 的属性（以避免 异常，禁用 SerializationFeature.FAIL_ON_EMPTY_BEANS

通常，当您模拟某个要测试的类的依赖项时，您模拟的是在您测试的类中使用的公共方法。 直接返回您的依赖项并不是一个好的现实世界用例 - 您不太可能必须编写这样的代码。

我猜你正在努力学习，所以让我提供一个改进的例子：

@RestController
public class ReservationController {
    @Autowired
    private ReservationService reservationService;     //my chnage here

    @RequestMapping(value = "/reservation", produces = MediaType.APPLICATION_JSON_UTF8_VALUE, method = RequestMethod.POST)
    @ResponseBody
    public Reservation getReservation() {

        return reservationService.getReservation();   //my chnage here
    }
}

您通常拥有一个包含一些业务逻辑并返回某些内容的服务类，而不是直接注入一个值对象 - 在我的示例中是 ReservationService，它有一个方法 getReservation()，该方法返回和类型为 Reservation 的对象。

有了这个，在你的测试中你可以模拟ReservationService。

@WebMvcTest
@RunWith(SpringRunner.class)
public class MvcTest {
    @Autowired
    private MockMvc mockMvc;

    @MockBean(name = "reservation")
    private ReservationService reservationService;    //my chnage here

    @Test
    public void postReservation() throws Exception {
        // You need that to specify what should your mock return when getReservation() is called. Without it you will get null
        when(reservationService.getReservation()).thenReturn(new Reservation()); //my chnage here

        mockMvc.perform(MockMvcRequestBuilders.post("/reservation"))
                .andExpect(MockMvcResultMatchers.content().contentType(MediaType.APPLICATION_JSON_UTF8_VALUE))
                .andExpect(MockMvcResultMatchers.status().isOk());
    }
}