unit test spring controller with WebTestClient and ControllerAdvice

Question

I'm trying to unit test my controller and the specific case which is : my service return a Mono.Empty, I throw a NotFoundException and I wan't to make sure I'm getting a 404 exception

here's my controller :

@GetMapping(path = "/{id}")
    public Mono<MyObject<JsonNode>> getFragmentById(@PathVariable(value = "id") String id) throws NotFoundException {

        return this.myService.getObject(id, JsonNode.class).switchIfEmpty(Mono.error(new NotFoundException()));

    }

Here's my controller advice :

@ControllerAdvice
public class RestResponseEntityExceptionHandler {

    @ExceptionHandler(value = { NotFoundException.class })
    protected ResponseEntity<String> handleNotFound(SaveActionException ex, WebRequest request) {
        String bodyOfResponse = "This should be application specific";
        return ResponseEntity.status(HttpStatus.NOT_FOUND).body("Resource not found");
    }

}

and my test :

@Before
    public void setup() {
        client = WebTestClient.bindToController(new MyController()).controllerAdvice(new RestResponseEntityExceptionHandler()).build();
    }
@Test
    public void assert_404() throws Exception {

        when(myService.getobject("id", JsonNode.class)).thenReturn(Mono.empty());

        WebTestClient.ResponseSpec response = client.get().uri("/api/object/id").exchange();
        response.expectStatus().isEqualTo(404);

    }

I'm getting a NotFoundException But a 500 error not a 404 which mean my advice hasn't been called

stack trace :

java.lang.AssertionError: Status expected:<404> but was:<500>

> GET /api/fragments/idFragment
> WebTestClient-Request-Id: [1]

No content

< 500 Internal Server Error
< Content-Type: [application/json;charset=UTF-8]

Content not available yet

any idea ?

Answer 1

I believe you can delete this controller advice and just have the following:

    @GetMapping(path = "/{id}")
    public Mono<MyObject<JsonNode>> getFragmentById(@PathVariable(value = "id") String id) {

        return this.myService.getObject(id, JsonNode.class)
                             .switchIfEmpty(Mono.error(new ResponseStatusException(HttpStatus.NOT_FOUND)));

    }

As for ResponseEntityExceptionHandler, this class is part of Spring MVC so I don't think you should use it in a WebFlux application.