SpringBootTest - Test exception when request is invalid - unit-testing

Question

I developed an API using web-flux which is working fine when I make request using POSTMAN. My code is:
Controller:
#PostMapping("/post", produces = ["application/xml"])
fun post(#Valid request: RequestData): Mono<Response> {
return Mono.just(request)
...
...
...
}
dto:
data class RequestData(
#get:NotBlank
#get:Email
val email: String = "",
)
So whenever I pass invalid email via POSTMAN, I'm catching the exception like below and its working:
#ExceptionHandler
fun bindingExceptionHandler(e: WebExchangeBindException) = "Custom Error Message"
But now when I write UT(#WebFluxTest) for this case (Invalid emaid), It failed.
#Test
fun testWhenInvalidEmail() {
// Request body
val email = "invalidemail"
val request = LinkedMultiValueMap<String, String>()
request.add("email", email)
webTestClient.post().uri("/post")
.body(BodyInserters.fromFormData(request))
.exchange()
.expectStatus().isOk
}
When I debug this, I found that my exceptionHandler not coming into picture when request coming through unit test. I'm using application/x-www-form-urlencoded content type in POST request.
Please let me know where I'm doing wrong.
I followed this question as well but didn't work.

Answer 1

As mentioned on another related question, this has been fixed in Spring Boot 2.1.0.
Also, you shouldn't have to build WebTestClient yourself but instead inject it in your test class (see reference documentation about that):
#RunWith(SpringRunner.class)
#WebFluxTest(MyValidationController.class)
public class MyValidationControllerTests {
#Autowired
private WebTestClient webClient;
#Test
public void testWhenInvalidEmail() {
//...
}
}