Mock error UnfinishedStubbingException in a Junit test

Question

I've created a test to try out my microservice. A simple get call that through 3 parameters returns me the message with the specifications of that user. I created it using Junit and Mockito. Below:

@Test
public void TestOk() throws Exception{
    CarsRequest carsRequest = new CarsRequest();
    carsRequest.setName(TestCostants.NAME);
    carsRequest.setPlate(TestCostants.PLATE);
    carsRequest.setPrice(TestCostants.PRICE);
    Cars car = new Cars("BMW","TG35647", "15000","re",80000000,
            null,null);
    List<Cars> cars = new ArrayList<>();
    cars.add(car);


    Mockito.when(
            service.getByPlate(carsRequest.getName(), carsRequest.getPlate(),
                    carsRequest.getPrice())).thenReturn(cars);
    RequestBuilder requestBuilder = MockMvcRequestBuilders.get(
            "/resources/cars").accept(
            MediaType.APPLICATION_JSON).header("Authorization","Basic //myAuth");
    MvcResult result = mockMvc.perform(requestBuilder).andReturn();
    System.out.println(result.getResponse());


    String expected = "{\"name\"=\"BMW\", \"plate\"=\"TG35647\", " +
            "\"price\"=\"15000\",\"brand\"=\"re\", \"kilometers\"=\"80000000\", \"revisiondate\"=\"null\", \"owner\"=\"null\"}";
    JSONAssert.assertEquals(expected, result.getResponse()
            .getContentAsString(), false);
});

clearly the constants of the variables that are passed conform to those of the message that must return me. When I try to start the test it gives me an error This is the stacktrace I am reporting:

2021-03-29 12:45:07.906 [main] INFO  o.s.s.l.SpringSecurityLdapTemplate - Ignoring PartialResultException
{
  "@timestamp" : "2021-03-29T12:45:08.119+02:00",
  "@version" : "1",
  "message" : "[GET] http://localhost/resources/cars/ call resulted in the following error: Content type '' not supported",
  "logger_name" : "my.project.car.controller.ExceptionHandlingController",
  "thread_name" : "main",
  "level" : "ERROR",
  "level_value" : 40000
}
ErrorResponse: org.springframework.web.HttpMediaTypeNotSupportedException: Content type '' not supported
org.springframework.mock.web.MockHttpServletResponse@135f160e
MockHttpServletRequest:
      HTTP Method = GET
      Request URI = /resources/cars/
       Parameters = {}
          Headers = [Accept:"application/json", Authorization:"Basic //myAuth"]
             Body = null
    Session Attrs = {}
Handler:
             Type = null
Async:
    Async started = false
     Async result = null
Resolved Exception:
             Type = org.springframework.web.HttpMediaTypeNotSupportedException
ModelAndView:
        View name = null
             View = null
            Model = null
FlashMap:
       Attributes = null
MockHttpServletResponse:
           Status = 500
    Error message = null
          Headers = [Content-Type:"application/json", X-Content-Type-Options:"nosniff", X-XSS-Protection:"1; mode=block", Cache-Control:"no-cache, no-store, max-age=0, must-revalidate", Pragma:"no-cache", Expires:"0", X-Frame-Options:"DENY"]
     Content type = application/json
             Body = {"esito":"KO","codiceEsito":"ERROR","descrizioneEsito":"Errore generico"}
    Forwarded URL = null
   Redirected URL = null
          Cookies = []
java.lang.AssertionError:
Expected: name
     but none found
 ;
Expected: plate
     but none found
 ;
Expected: price
     but none found
 ;
Expected: brand
     but none found
 ;
Expected: kilometers
     but none found
 ;
Expected: revisiondate
     but none found
 ;
Expected: owner
     but none found
 ;

Trying to go to Debug, I get this error back, but I don't know how to handle it at all

Method threw 'org.mockito.exceptions.misusing.UnfinishedStubbingException' exception. Cannot evaluate my.project.service.CarService$MockitoMock$1824138024.toString()

I guess the two errors are related but I don't know how to fix this.

EDIT: As requested, I add my Car Service:

@Service
public class CarService {
    @Autowired
    CarRepository carRepository;
    @Autowired
    ObjectMapper objectMapper;

    public List<Car> getByPlate(String name, String plate, String price) throws JsonProcessingException {
        List<Car> car = new ArrayList<>();
        for (Cache.Entry<String, Car> entry: carRepository.findAllByNameAndPlateAndPrice(name, plate,price)){
            car.add(new Car(entry.getKey(), entry.getValue()));
            System.out.println("Entry: " + objectMapper.writeValueAsString(entry));
        }
        return cars;
    }
}

and my CarController

@RestController
@RequestMapping("/resources/")
public class CarController {
    @Autowired
    CarService carService;
    @Autowired
    ObjectMapper objectMapper;
    @GetMapping(
    value = "/cars",
    consumes = {MediaType.APPLICATION_JSON_VALUE},
    produces = {MediaType.APPLICATION_JSON_VALUE})
    public CarsResponse getCars(@RequestBody CarsRequest request) throws IOException {
        //some code
    }

Answer 1

First of all, using GET requests with a body is the poor practice. Use POST requests instead.

Then, spring tells you about org.springframework.web.HttpMediaTypeNotSupportedException and in your controller method getCars() you describe the next:

    consumes = {MediaType.APPLICATION_JSON_VALUE},
    produces = {MediaType.APPLICATION_JSON_VALUE}

But in your test you don't specify any content-type:

RequestBuilder requestBuilder = MockMvcRequestBuilders.get(
        "/resources/cars").accept(
        MediaType.APPLICATION_JSON).header("Authorization","Basic //myAuth");

Try to add content-type .contentType(MediaType.APPLICATION_JSON):

 RequestBuilder requestBuilder = MockMvcRequestBuilders.get("/resources/cars")
                .accept(MediaType.APPLICATION_JSON)
                .contentType(MediaType.APPLICATION_JSON)
                .header("Authorization", "Basic //myAuth");

Also, I don't see how you pass the body to the request. Try to add it .content(mapper.writeValueAsString(carsRequest)):

 RequestBuilder requestBuilder = MockMvcRequestBuilders.get("/resources/cars")
                .accept(MediaType.APPLICATION_JSON)
                .contentType(MediaType.APPLICATION_JSON)
                .header("Authorization", "Basic //myAuth")
                .content(mapper.writeValueAsString(carsRequest));

where mapper is ObjectMapper. I assume you are using com.fasterxml.jackson.databind.ObjectMapper.

Answer 2

You need to do the argument matching properly. You probably want to test, whether or not the parameters are equal to, and not if they are the same as the parameters you defined in your test class. Try this:

Mockito.when(service.getByPlate(Mockito.eq(carsRequest.getName()), Mockito.eq(carsRequest.getPlate()), Mockito.eq(carsRequest.getPrice()))).thenReturn(cars);