fix : 동일 멘토 멘티 중복 신청 불가능하도록 수정

src/main/java/com/example/solidconnection/common/exception/ErrorCode.java

@@ -118,6 +118,7 @@ public enum ErrorCode {
     CHANNEL_SEQUENCE_NOT_UNIQUE(HttpStatus.BAD_REQUEST.value(), "채널의 순서가 중복되었습니다."),
     CHANNEL_REGISTRATION_LIMIT_EXCEEDED(HttpStatus.BAD_REQUEST.value(), "등록 가능한 채널 수를 초과하였습니다."),
     ALREADY_MENTOR(HttpStatus.BAD_REQUEST.value(), "이미 멘토로 등록된 사용자입니다."),
+    ALREADY_EXIST_MENTORING(HttpStatus.BAD_REQUEST.value(), "이미 신청된 멘티, 멘토입니다."),
     MENTORING_NOT_FOUND(HttpStatus.NOT_FOUND.value(), "해당 멘토링 신청을 찾을 수 없습니다."),
     UNAUTHORIZED_MENTORING(HttpStatus.FORBIDDEN.value(), "멘토링 권한이 없습니다."),
     MENTORING_ALREADY_CONFIRMED(HttpStatus.BAD_REQUEST.value(), "이미 승인 또는 거절된 멘토링입니다."),

src/main/java/com/example/solidconnection/mentor/domain/Mentoring.java

@@ -13,6 +13,8 @@
 import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+import jakarta.persistence.UniqueConstraint;
 import java.time.ZonedDateTime;
 import lombok.AccessLevel;
 import lombok.AllArgsConstructor;
@@ -27,29 +29,35 @@
 @DynamicInsert
 @AllArgsConstructor
 @NoArgsConstructor(access = AccessLevel.PROTECTED)
+@Table(name = "mentoring", uniqueConstraints = {
+        @UniqueConstraint(
+                name = "uk_mentoring_mentor_id_mentee_id",
+                columnNames = {"mentor_id", "mentee_id"}
+        )
+})
 public class Mentoring extends BaseEntity {
 
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
 
-    @Column
+    @Column(name="confirmed_at")
     private ZonedDateTime confirmedAt;
 
-    @Column
+    @Column(name = "checked_at_by_mentor")
     private ZonedDateTime checkedAtByMentor;
 
-    @Column
+    @Column(name = "checked_at_by_mentee")
     private ZonedDateTime checkedAtByMentee;
 
-    @Column(nullable = false)
+    @Column(nullable = false, name="verify_status")
     @Enumerated(EnumType.STRING)
     private VerifyStatus verifyStatus = VerifyStatus.PENDING;
 
-    @Column
+    @Column(name = "mentor_id")
     private long mentorId;
 
-    @Column
+    @Column(name = "mentee_id")
     private long menteeId;
 
     public Mentoring(long mentorId, long menteeId, VerifyStatus verifyStatus) {

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

@@ -1,5 +1,6 @@
 package com.example.solidconnection.mentor.service;
 
+import static com.example.solidconnection.common.exception.ErrorCode.ALREADY_EXIST_MENTORING;
 import static com.example.solidconnection.common.exception.ErrorCode.MENTORING_ALREADY_CONFIRMED;
 import static com.example.solidconnection.common.exception.ErrorCode.MENTORING_NOT_FOUND;
 import static com.example.solidconnection.common.exception.ErrorCode.MENTOR_NOT_FOUND;
@@ -30,8 +31,13 @@ public class MentoringCommandService {
 
     @Transactional
     public MentoringApplyResponse applyMentoring(long siteUserId, MentoringApplyRequest mentoringApplyRequest) {
-        Mentoring mentoring = new Mentoring(mentoringApplyRequest.mentorId(), siteUserId, VerifyStatus.PENDING);
+        long mentorId = mentoringApplyRequest.mentorId();
+
+        if (mentoringRepository.existsByMentorIdAndMenteeId(mentorId, siteUserId)) {
+            throw new CustomException(ALREADY_EXIST_MENTORING);
+        }
 
+        Mentoring mentoring = new Mentoring(mentoringApplyRequest.mentorId(), siteUserId, VerifyStatus.PENDING);
         return MentoringApplyResponse.from(mentoringRepository.save(mentoring));
     }
 

src/main/resources/db/migration/V37__add_unique_constraint_to_mentor_id_mentee_id.sql

@@ -0,0 +1,3 @@
+ALTER TABLE mentoring
+ADD CONSTRAINT uk_mentoring_mentor_id_mentee_id
+UNIQUE (mentor_id, mentee_id);

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

@@ -1,5 +1,6 @@
 package com.example.solidconnection.mentor.service;
 
+import static com.example.solidconnection.common.exception.ErrorCode.ALREADY_EXIST_MENTORING;
 import static com.example.solidconnection.common.exception.ErrorCode.MENTORING_ALREADY_CONFIRMED;
 import static com.example.solidconnection.common.exception.ErrorCode.MENTORING_NOT_FOUND;
 import static com.example.solidconnection.common.exception.ErrorCode.UNAUTHORIZED_MENTORING;
@@ -96,6 +97,18 @@ class 멘토링_신청_테스트 {
                     () -> assertThat(mentoring.getVerifyStatus()).isEqualTo(VerifyStatus.PENDING)
             );
         }
+
+        @Test
+        void 동일_멘티_멘토끼리는_재신청되지않는다() {
+            // given
+            mentoringFixture.대기중_멘토링(mentor1.getId(), menteeUser.getId());
+            MentoringApplyRequest request = new MentoringApplyRequest(mentor1.getId());
+
+            // when & then
+            assertThatThrownBy(() -> mentoringCommandService.applyMentoring(menteeUser.getId(), request))
+                    .isInstanceOf(CustomException.class)
+                    .hasMessage(ALREADY_EXIST_MENTORING.getMessage());
+        }
     }
 
     @Nested