如何使用 mockito 抛出 JsonProcessingException

Question

i have this lines in my code:

@Autowired
private ObjectMapper mapper = new ObjectMapper();

@PostMapping("/postPrueba")
public ResponseEntity<String> postPrueba(@RequestBody Prueba prueba) {

    String pTest = null;
    try {
        pTest  = mapper.writeValueAsString(prueba);
        System.out.println(pTest  );
    } catch (JsonProcessingException e) {
        return new ResponseEntity<>("", HttpStatus.INTERNAL_SERVER_ERROR);
    }
        return new ResponseEntity<>("", HttpStatus.OK);
}

My model Prueba.java

public class Prueba {

    @Id
    private String nombre;
    private String apellidos;
    private String edad;
}

And in test i want to force the JsonProcessingException but i can´t. I already try this:

@Mock
private ObjectMapper mapperMock;

@Test
public void testKo() throws Exception {

    ObjectMapper om = Mockito.spy(new ObjectMapper());
    Mockito.when(this.mapperMock.writeValueAsString(Mockito.any())).thenThrow(new JsonProcessingException("") {});

    ObjectMapper om = Mockito.spy(new ObjectMapper());
    Mockito.when( om.writeValueAsString(Mockito.eq(Prueba.class))).thenThrow(new JsonProcessingException("") {});

    Mockito.when(this.mapperMock.writeValueAsString(Mockito.eq(Prueba.class))).thenThrow(new JsonProcessingException("") {});

    String jsonContent = "{'nombre': '123456', 'apellidos': '12'}";
    jsonContent = jsonContent.replaceAll("\'", "\"");

    this.mvc.perform(post("/postPrueba")
                .contentType(MediaType.APPLICATION_JSON)
                .content(jsonContent))
                .andExpect(status().is5xxServerError());
    }

But always the response is a 200 OK. How can i do this?

Answer 1

You'll need to mock your http behaviour because the ObjectMapper is out of the scope. Found WireMock fits your purpose in terms of filtering http traffic and mocking responses

Answer 2

而不是从测试中抛出JsonProcessingException只是让ObjectMapper实际上抛出该异常并带有一些要处理的错误数据。

Answer 3

You need to replace the Bean in the spring context.

I assume you use Spring Boot with @RunWith(SpringRunner.class) and @WebMVCTest?

Then you can do this using @MockBean

See also: https://www.baeldung.com/java-spring-mockito-mock-mockbean

Answer 4

尝试这个：

Mockito.doThrow(JsonProcessingException.class).when(this.mapperMock).writeValueAsString(Mockito.any());

Answer 5

  doThrow(JsonProcessingException.class).when(object).method(...);