Assertions on RaabitMQ Listener message received in Spring Boot Integration tests behaves strange - spring-boot

Question

I've a RabbitMq listener which receives message from queue succesfully but fails on Assertion in Spring Boot Integration.
I'm adding every message received on the queue to list. But at the assertion, list is empty.
Below are my classes :
#Component
public class NotificationEventListener {
private List<MigrationEvent> queuedEvents = new ArrayList<>();
#RabbitListener(queues = "queue-name", concurrency = "1")
public void handleNotificationEvent(#Payload final MigrationEvent migrationEvent) {
queuedEvents.add(0, migrationEvent);
}
public MigrationEvent getLatestMigrationEvent() {
return queuedEvents.get(0);
}
}
This is in the Integration Test class
ExtendWith(SpringExtension.class)
#SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
#AutoConfigureMockMvc
public class ControllerTest {
#Autowired
protected NotificationEventListener listener;
#Test
void givenUserMigrationStateExist_whenCallPostPlm_thenUserStateInQueueShouldBeReturned() throws Exception {
final var userUid = TestDataGenerator.generateUserUid();
final var txId = TestDataGenerator.generateCorrelationId();
final var messageCount = getAllMigrationEvents().size();
final var response = assertQueueUserSuccess(userUid, txId);
//above line calls an http end point in the server code and puts message onto rabbit queue
assertMigrationEventOnQueue(userUid, txId);//fails here the list is empty
assertThat((getAllMigrationEvents().size() - messageCount)).isEqualTo(1);
}
protected void assertMigrationEventOnQueue(final String userUid, final String txId) {
assertThat(listener.getLatestMigrationEvent().getUseruid()).isEqualTo(userUid);
assertThat(listener.getLatestMigrationEvent().getCorrelationId()).isEqualTo(txId)));
}
I can assure this is not the case of delay because putting loggers in I could receive the message and add it to the list. But At the time of assertion in test class it fails saying list is empty.
This seems like there are two different processes running, one verifying and other listening. Is that something with the listener ?