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;
    }
}

其中保留是一个简单的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 + "]";
    }
}

@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());
    }
}

........

原因：com.fasterxml.jackson.databind.exc.InvalidDefinitionException：找不到类org.mockito.internal.debugging.locationImpl的序列化程序，也找不到创建BeanSerializer的属性（若要避免异常，请禁用SerializationFeature.fail_on_empty_beans）（通过引用链：spring.boot.usingspringboot.entity.reservation$mockitomock$980801978[“mockitointerceptor”]->

如何才能以正确的方式注入预订？？

谢谢你

Answer 1

之所以会出现错误，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。该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，默认情况下返回其返回类型的默认值（例如，对象为null，int为1，等等），或者对void方法不执行任何操作。

杰克逊正在抱怨，因为它要连载这个没有字段的代理，杰克逊不知道该怎么做。

com.fasterxml.jackson.databind.exc.InvalidDefinitionException：找不到org.mockito.internal.debugging.LocationImpl类的序列化程序，也找不到创建BeanSerializer的属性（若要避免异常，请禁用SerializationFeature.fail_on_empty_beans

通常，当模拟某个要测试的类的依赖项时，模拟的是在所测试的类中使用的公共方法。直接返回依赖项并不是一个好的真实世界用例--您不太可能必须编写这样的代码。

我想您正在尝试学习，所以让我提供一个改进的示例：

@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
    }
}

通常不是直接注入值对象，而是使用包含一些业务逻辑并返回某些内容的服务类--在我的示例中，ReservationService有一个方法getReservation()返回Reservation和类型为Reservation的对象。

这样，在测试中就可以模拟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());
    }
}