Spring-Webflux: Handler function unit test is throwing UnsupportedMediaTypeStatusException - unit-testing

Question

I am trying to write Unit test to the handler function, I followed the example from the Spring project. Can someone help me why the following test is throwing UnsupportedMediaTypeStatusException?
Thanks
Handler function
public Mono<ServerResponse> handle(ServerRequest serverRequest) {
log.info("{} Processing create request", serverRequest.exchange().getLogPrefix());
return ok().body(serverRequest.bodyToMono(Person.class).map(p -> p.toBuilder().id(UUID.randomUUID().toString()).build()), Person.class);
}
Test Class
#SpringBootTest
#RunWith(SpringRunner.class)
public class MyHandlerTest {
#Autowired
private MyHandler myHandler;
private ServerResponse.Context context;
#Before
public void createContext() {
HandlerStrategies strategies = HandlerStrategies.withDefaults();
context = new ServerResponse.Context() {
#Override
public List<HttpMessageWriter<?>> messageWriters() {
return strategies.messageWriters();
}
#Override
public List<ViewResolver> viewResolvers() {
return strategies.viewResolvers();
}
};
}
#Test
public void handle() {
Gson gson = new Gson();
MockServerWebExchange exchange = MockServerWebExchange.from(
MockServerHttpRequest.post("/api/create")
.body(gson.toJson(Person.builder().firstName("Jon").lastName("Doe").build())));
MockServerHttpResponse mockResponse = exchange.getResponse();
ServerRequest serverRequest = ServerRequest.create(exchange, HandlerStrategies.withDefaults().messageReaders());
Mono<ServerResponse> serverResponseMono = myHandler.handle(serverRequest);
Mono<Void> voidMono = serverResponseMono.flatMap(response -> {
assertThat(response.statusCode()).isEqualTo(HttpStatus.OK);
boolean condition = response instanceof EntityResponse;
assertThat(condition).isTrue();
return response.writeTo(exchange, context);
});
StepVerifier.create(voidMono)
.expectComplete().verify();
StepVerifier.create(mockResponse.getBody())
.consumeNextWith(a -> System.out.println(a))
.expectComplete().verify();
assertThat(mockResponse.getHeaders().getContentType()).isEqualTo(MediaType.APPLICATION_JSON);
}
}
Error Message:
java.lang.AssertionError: expectation "expectComplete" failed (expected: onComplete(); actual: onError(org.springframework.web.server.UnsupportedMediaTypeStatusException: 415 UNSUPPORTED_MEDIA_TYPE "Content type 'application/octet-stream' not supported for bodyType=com.example.demo.Person"))

Answer 1

I found that I missed .contentType(MediaType.APPLICATION_JSON) to my mock request.
MockServerWebExchange.from(
MockServerHttpRequest.post("/api/create").contentType(MediaType.APPLICATION_JSON)
.body(gson.toJson(Person.builder().firstName("Jon").lastName("Doe").build())));
fixed my issue.