Zoned time gets converted to UTC in Spring Integration test - spring-boot

Question

I'm trying to verify that my reactive rest controller transfers the correct data. This data contains a ZonedDateTime field I need to retain. However, when querying the rest controller with a WebTestClient, my verification fails because the received time is suddenly in UTC.
#Data
public class SimpleData {
ZonedDateTime zdt;
}
#RestController
class SimpleDataController {
#Autowired SimpleDataService service;
#GetMapping("/simple")
List<SimpleData> getData() {
return service.getTimes();
}
}
#Service
class SimpleDataService {
public static final SimpleData DATA = new SimpleData();
static {
DATA.setZdt(ZonedDateTime.now(ZoneId.of("Europe/Berlin")));
}
public List<SimpleData> getTimes() {
return List.of(DATA);
}
}
#SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.DEFINED_PORT)
#ActiveProfiles("test")
class ApplicationTests {
#Test
void simpleDataTest() {
List<SimpleData> fromRest = WebTestClient.bindToServer().baseUrl("http://localhost:8080").build()
.get().uri("/simple").exchange()
.expectBodyList(SimpleData.class)
.returnResult().getResponseBody();
assertThat(fromRest).containsAll(Collections.singletonList(SimpleDataService.DATA));
}
}
This fails with
Expecting ArrayList:
<[SimpleData(zdt=2020-08-05T09:30:40.291415300Z[UTC])]> to contain:
<[SimpleData(zdt=2020-08-05T11:30:40.291415300+02:00[Europe/Berlin])]>
but could not find the following element(s):
<[SimpleData(zdt=2020-08-05T11:30:40.291415300+02:00[Europe/Berlin])]>
The time itself is correct - the time zone difference is substracted from the hour field - but it fails the equals obviously. Funnily enough, if you query the url with a client, the JSON contains the correct data:
[{"zdt":"2020-08-05T11:44:10.4740259+02:00"}]
It seems to be the TestWebClient converting the time.
Is this intended? Can I change this behaviour somehow?

Answer 1

In summary, ADJUST_DATES_TO_CONTEXT_TIME_ZONE alone is not sufficient, WebTestClient should not be created manually and instead it should use #AutoConfigureWebTestClient and autowire the client.
#SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.DEFINED_PORT)
#ActiveProfiles("test")
#AutoConfigureWebTestClient
class ApplicationTests {
#Autowired
private WebTestClient client;
#Test
void simpleDataTest() {
List<SimpleData> fromRest = client.
.get().uri("/simple").exchange()
.expectBodyList(SimpleData.class)
.returnResult().getResponseBody();
assertThat(fromRest)
.containsAll(singletonList(SimpleDataService.DATA));
}
}
application.properties
spring.jackson.deserialization.ADJUST_DATES_TO_CONTEXT_TIME_ZONE = false

Answer 2

I couldn't sleep without getting a solution for this. So here you go! A working solution to your problem. :)
#JsonComponent
class ZonedDateTimeJsonSerializer extends JsonSerializer<ZonedDateTime> {
static DateTimeFormatter formatter = DateTimeFormatter.ISO_ZONED_DATE_TIME;
#Override
public void serialize(ZonedDateTime zdt, JsonGenerator jsonGenerator,
SerializerProvider serializerProvider) throws IOException,
JsonProcessingException {
jsonGenerator.writeString(zdt.format(formatter));
}
}
#JsonComponent
class ZonedDateTimeJsonDeserializer extends JsonDeserializer<ZonedDateTime> {
static DateTimeFormatter formatter = DateTimeFormatter.ISO_ZONED_DATE_TIME;
#Override
public ZonedDateTime deserialize(JsonParser p, DeserializationContext ctxt)
throws IOException, JsonProcessingException {
return ZonedDateTime.parse(p.getValueAsString(),formatter);
}
}
#SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.DEFINED_PORT)
#ActiveProfiles("test")
#AutoConfigureWebTestClient
class ApplicationTests {
#Autowired
private WebTestClient client; // important! as the #jsonComponent has to be picked up
#Test
void simpleDataTest() {
List<SimpleData> fromRest = client.
.get().uri("/simple").exchange()
.expectBodyList(SimpleData.class)
.returnResult().getResponseBody();
assertThat(fromRest)
.containsAll(singletonList(SimpleDataService.DATA));
}
}