refactor: 채팅방 생성 동기식으로 변경

src/main/java/com/example/solidconnection/chat/repository/ChatRoomRepository.java

@@ -34,7 +34,7 @@ SELECT COUNT(cm) FROM ChatMessage cm
            """)
     long countUnreadMessages(@Param("chatRoomId") long chatRoomId, @Param("userId") long userId);
 
-    boolean existsByMentoringId(long mentoringId);
+    ChatRoom findByMentoringId(long mentoringId);
 
     List<ChatRoom> findAllByMentoringIdIn(List<Long> mentoringIds);
 }

src/main/java/com/example/solidconnection/chat/service/ChatService.java

@@ -174,15 +174,20 @@ public void sendChatMessage(ChatMessageSendRequest chatMessageSendRequest, long
     }
 
     @Transactional
-    public void createMentoringChatRoom(Long mentoringId, Long mentorId, Long menteeId) {
-        if (chatRoomRepository.existsByMentoringId(mentoringId)) {
-            return;
+    public Long createMentoringChatRoom(Long mentoringId, Long mentorId, Long menteeId) {
+        ChatRoom existingChatRoom = chatRoomRepository.findByMentoringId(mentoringId);
+        if (existingChatRoom != null) {
+            return existingChatRoom.getId();
         }
 
+        // 새 채팅방 생성
         ChatRoom chatRoom = new ChatRoom(mentoringId, false);
         chatRoom = chatRoomRepository.save(chatRoom);
+
         ChatParticipant mentorParticipant = new ChatParticipant(mentorId, chatRoom);
         ChatParticipant menteeParticipant = new ChatParticipant(menteeId, chatRoom);
         chatParticipantRepository.saveAll(List.of(mentorParticipant, menteeParticipant));
+
+        return chatRoom.getId();
     }
 }

src/main/java/com/example/solidconnection/mentor/dto/MentoringConfirmResponse.java

@@ -1,12 +1,18 @@
 package com.example.solidconnection.mentor.dto;
 
+import static com.fasterxml.jackson.annotation.JsonInclude.Include.NON_NULL;
+
 import com.example.solidconnection.mentor.domain.Mentoring;
+import com.fasterxml.jackson.annotation.JsonInclude;
 
 public record MentoringConfirmResponse(
-        long mentoringId
+        long mentoringId,
+
+        @JsonInclude(NON_NULL)
+        Long chatRoomId
 ) {
 
-    public static MentoringConfirmResponse from(Mentoring mentoring) {
-        return new MentoringConfirmResponse(mentoring.getId());
+    public static MentoringConfirmResponse from(Mentoring mentoring, Long chatRoomId) {
+        return new MentoringConfirmResponse(mentoring.getId(), chatRoomId);
     }
 }

src/main/java/com/example/solidconnection/mentor/service/MentoringCommandService.java

@@ -5,19 +5,18 @@
 import static com.example.solidconnection.common.exception.ErrorCode.MENTOR_NOT_FOUND;
 import static com.example.solidconnection.common.exception.ErrorCode.UNAUTHORIZED_MENTORING;
 
+import com.example.solidconnection.chat.service.ChatService;
 import com.example.solidconnection.common.VerifyStatus;
 import com.example.solidconnection.common.exception.CustomException;
 import com.example.solidconnection.mentor.domain.Mentor;
 import com.example.solidconnection.mentor.domain.Mentoring;
 import com.example.solidconnection.mentor.dto.MentoringApplyRequest;
 import com.example.solidconnection.mentor.dto.MentoringApplyResponse;
-import com.example.solidconnection.mentor.dto.MentoringApprovedEvent;
 import com.example.solidconnection.mentor.dto.MentoringConfirmRequest;
 import com.example.solidconnection.mentor.dto.MentoringConfirmResponse;
 import com.example.solidconnection.mentor.repository.MentorRepository;
 import com.example.solidconnection.mentor.repository.MentoringRepository;
 import lombok.RequiredArgsConstructor;
-import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -27,7 +26,7 @@ public class MentoringCommandService {
 
     private final MentoringRepository mentoringRepository;
     private final MentorRepository mentorRepository;
-    private final ApplicationEventPublisher eventPublisher;
+    private final ChatService chatService;
 
     @Transactional
     public MentoringApplyResponse applyMentoring(long siteUserId, MentoringApplyRequest mentoringApplyRequest) {
@@ -49,12 +48,13 @@ public MentoringConfirmResponse confirmMentoring(long siteUserId, long mentoring
 
         mentoring.confirm(mentoringConfirmRequest.status());
 
+        Long chatRoomId = null;
         if (mentoringConfirmRequest.status() == VerifyStatus.APPROVED) {
             mentor.increaseMenteeCount();
-            eventPublisher.publishEvent(MentoringApprovedEvent.of(mentoringId, mentor.getSiteUserId(), mentoring.getMenteeId()));
+            chatRoomId = chatService.createMentoringChatRoom(mentoringId, mentor.getSiteUserId(), mentoring.getMenteeId());
         }
 
-        return MentoringConfirmResponse.from(mentoring);
+        return MentoringConfirmResponse.from(mentoring, chatRoomId);
     }
 
     private void validateMentoringNotConfirmed(Mentoring mentoring) {

src/test/java/com/example/solidconnection/mentor/service/MentoringCommandServiceTest.java

@@ -134,23 +134,17 @@ class 멘토링_승인_거절_테스트 {
             assertThat(beforeChatRoom).isEmpty();
 
             // when
-            mentoringCommandService.confirmMentoring(mentorUser1.getId(), mentoring.getId(), request);
+            MentoringConfirmResponse response = mentoringCommandService.confirmMentoring(mentorUser1.getId(), mentoring.getId(), request);
 
             // then
-            ChatRoom afterChatRoom = await()
-                    .atMost(Duration.ofSeconds(5))
-                    .pollInterval(Duration.ofMillis(100))
-                    .until(() -> chatRoomRepositoryForTest
-                                   .findOneOnOneChatRoomByParticipants(mentorUser1.getId(), menteeUser.getId()),
-                           Optional::isPresent)
-                    .orElseThrow();
-
+            ChatRoom afterChatRoom = chatRoomRepositoryForTest.findOneOnOneChatRoomByParticipants(mentorUser1.getId(), menteeUser.getId()).orElseThrow();
             List<Long> participantIds = afterChatRoom.getChatParticipants().stream()
                     .map(ChatParticipant::getSiteUserId)
                     .toList();
             assertAll(
                     () -> assertThat(afterChatRoom.isGroup()).isFalse(),
-                    () -> assertThat(participantIds).containsExactly(mentorUser1.getId(), menteeUser.getId())
+                    () -> assertThat(participantIds).containsExactly(mentorUser1.getId(), menteeUser.getId()),
+                    () -> assertThat(response.chatRoomId()).isEqualTo(afterChatRoom.getId())
             );
         }
 
@@ -186,19 +180,14 @@ class 멘토링_승인_거절_테스트 {
             assertThat(beforeChatRoom).isEmpty();
 
             // when
-            mentoringCommandService.confirmMentoring(mentorUser1.getId(), mentoring.getId(), request);
+            MentoringConfirmResponse response = mentoringCommandService.confirmMentoring(mentorUser1.getId(), mentoring.getId(), request);
 
             // then
-            await()
-                    .pollInterval(Duration.ofMillis(100))
-                    .during(Duration.ofSeconds(1))
-                    .until(() -> chatRoomRepositoryForTest
-                                         .findOneOnOneChatRoomByParticipants(mentorUser1.getId(), menteeUser.getId())
-                                         .isEmpty());
-
             Optional<ChatRoom> afterChatRoom = chatRoomRepositoryForTest.findOneOnOneChatRoomByParticipants(mentorUser1.getId(), menteeUser.getId());
-            assertThat(afterChatRoom).isEmpty();
-
+            assertAll(
+                    () -> assertThat(response.chatRoomId()).isNull(),
+                    () -> assertThat(afterChatRoom).isEmpty()
+            );
         }
 
         @Test