[#180][FEATURE] 그룹 탈퇴

src/asciidoc/api/group.adoc

@@ -84,6 +84,27 @@ include::{snippets}/group-controller-rest-docs-test/create-group_success/http-re
 include::{snippets}/group-controller-rest-docs-test/create-group_success/response-headers.adoc[]
 include::{snippets}/group-controller-rest-docs-test/create-group_success/http-response.adoc[]
 
+==== 1-3. 그룹 탈퇴
+
+*Description* +
+
+'''
+
+그룹 탈퇴를 위해 사용합니다. 그룹장은 그룹을 탈퇴할 수 없습니다.
+
+*Request* +
+
+'''
+
+include::{snippets}/group-entry-controller-rest-docs-test/leave-group_success/http-request.adoc[]
+include::{snippets}/group-entry-controller-rest-docs-test/leave-group_success/path-parameters.adoc[]
+
+*Response* +
+
+'''
+
+include::{snippets}/group-entry-controller-rest-docs-test/leave-group_success/http-response.adoc[]
+
 === 2. 그룹 가입 관련 API
 
 ==== 2-1. 초대 코드 생성

src/main/java/com/studypals/domain/groupManage/api/GroupEntryController.java

@@ -27,6 +27,7 @@
  *     - POST /groups/{groupId}/entry-code : 그룹 초대 코드 생성
  *     - GET /groups/summary : 그룹 대표 정보 조회
  *     - POST /groups/join : 공개 그룹에 가입
+ *     - DELETE /groups/{groupId}/leave : 그룹 탈퇴
  *     - POST /groups/entry-requests : 비공개 그룹 가입 요청
  *     - GET /groups/{groupId}/entry-requests : 그룹 가입 요청 목록 조회
  *     - POST /groups/entry-requests/{requestId}/accept : 그룹 가입 요청 승인
@@ -82,6 +83,13 @@ public ResponseEntity<Void> joinGroup(@AuthenticationPrincipal Long userId, @Val
                 .build();
     }
 
+    @DeleteMapping("/{groupId}/leave")
+    public ResponseEntity<Void> leaveGroup(@AuthenticationPrincipal Long userId, @PathVariable Long groupId) {
+        groupEntryService.leaveGroup(userId, groupId);
+
+        return ResponseEntity.noContent().build();
+    }
+
     @PostMapping("/entry-requests")
     public ResponseEntity<Void> requestGroupParticipant(
             @AuthenticationPrincipal Long userId, @Valid @RequestBody GroupEntryReq req) {

src/main/java/com/studypals/domain/groupManage/service/GroupEntryService.java

@@ -56,6 +56,14 @@ public interface GroupEntryService {
      */
     Long joinGroup(Long userId, GroupEntryReq entryInfo);
 
+    /**
+     * 가입된 그룹에서 탈퇴합니다.
+     * 그룹장은 탈퇴할 수 없습니다.
+     * @param userId 그룹 멤버 ID
+     * @param groupId 탈퇴할 그룹 ID
+     */
+    void leaveGroup(Long userId, Long groupId);
+
     /**
      * 비공개 그룹에 가입 요청을 보냅니다.
      *

src/main/java/com/studypals/domain/groupManage/service/GroupEntryServiceImpl.java

@@ -96,6 +96,16 @@ public Long joinGroup(Long userId, GroupEntryReq entryInfo) {
         return internalJoinGroup(member, group);
     }
 
+    @Override
+    @Transactional
+    public void leaveGroup(Long userId, Long groupId){
+        Group group = groupReader.getById(groupId);
+        Member member = memberReader.getRef(userId);
+
+        chatRoomWriter.leave(group.getChatRoom(), member);
+        groupMemberWriter.deleteMember(userId, group);
+    }
+
     @Override
     @Transactional
     public Long requestParticipant(Long userId, GroupEntryReq entryInfo) {

src/main/java/com/studypals/domain/groupManage/worker/GroupMemberWriter.java

@@ -54,4 +54,17 @@ private GroupMember create(Member member, Group group, GroupRole role) {
         }
         return groupMember;
     }
+
+    public void deleteMember(Long userId, Group group) {
+        GroupMember groupMember = groupMemberRepository.findByMemberIdAndGroupId(userId, group.getId())
+                .orElseThrow(() -> {
+                    String message = String.format(
+                            "[GroupMemberWriter#deleteMember] member %d not found in group %d", userId, group.getId());
+                    return new GroupException(GroupErrorCode.GROUP_MEMBER_NOT_FOUND, message);
+                });
+        if(groupMember.isLeader()) {
+            throw new GroupException(GroupErrorCode.GROUP_LEAVE_FAIL, "leader can't leave the group");
+        }
+        groupMemberRepository.delete(groupMember);
+    }
 }

src/test/java/com/studypals/domain/groupManage/restDocsTest/GroupEntryControllerRestDocsTest.java

@@ -186,6 +186,25 @@ void joinGroup_success() throws Exception {
                         responseHeaders(headerWithName("Location").description("추가된 그룹 멤버 id"))));
     }
 
+    @Test
+    @WithMockUser
+    void leaveGroup_success() throws Exception {
+        // given
+        Long groupId = 1L;
+
+        // when
+        ResultActions result = mockMvc.perform(delete("/groups/{groupId}/leave", groupId));
+
+        // then
+        result.andExpect(status().isNoContent())
+                .andDo(restDocs.document(
+                        httpRequest(),
+                        httpResponse(),
+                        pathParameters(parameterWithName("groupId")
+                                .description("탈퇴할 그룹 ID")
+                                .attributes(constraints("not null")))));
+    }
+
     @Test
     @WithMockUser
     void requestParticipant_success() throws Exception {

src/test/java/com/studypals/domain/groupManage/service/GroupEntryServiceTest.java

@@ -240,6 +240,33 @@ void joinGroup_fail_groupMemberLimitExceed() {
                 .isEqualTo(GroupErrorCode.GROUP_JOIN_FAIL);
     }
 
+    @Test
+    void leaveGroup_success() {
+        // given
+        Long userId = 1L;
+        Long groupId = 1L;
+        Group group = Group.builder()
+                .id(groupId)
+                .totalMember(10)
+                .maxMember(10)
+                .isApprovalRequired(false)
+                .build();
+        Member member = Member.builder()
+                .id(userId)
+                .build();
+        group.setChatRoom(mockChatRoom);
+
+        given(groupReader.getById(groupId)).willReturn(group);
+        given(memberReader.getRef(userId)).willReturn(member);
+
+        // when
+        groupEntryService.leaveGroup(userId, groupId);
+
+        // then
+        verify(chatRoomWriter).leave(mockChatRoom, member);
+        verify(groupMemberWriter).deleteMember(userId, group);
+    }
+
     @Test
     void requestParticipant_success() {
         // given

src/test/java/com/studypals/domain/groupManage/worker/GroupMemberWriterTest.java

@@ -3,6 +3,9 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.verify;
+
+import java.util.Optional;
 
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
@@ -126,7 +129,6 @@ void createMember_fail_whileSave() {
     @Test
     void createMember_fail_memberLimitExceed() {
         // given
-        Long memberId = 1L;
         Long groupId = 1L;
         GroupErrorCode errorCode = GroupErrorCode.GROUP_JOIN_FAIL;
 
@@ -139,4 +141,39 @@ void createMember_fail_memberLimitExceed() {
                 .extracting("errorCode")
                 .isEqualTo(errorCode);
     }
+
+    @Test
+    void deleteMember_success() {
+        // given
+        Long userId = 1L;
+        Long groupId = 1L;
+
+        given(mockGroup.getId()).willReturn(groupId);
+        given(groupMemberRepository.findByMemberIdAndGroupId(userId, groupId)).willReturn(Optional.of(mockGroupMember));
+        given(mockGroupMember.isLeader()).willReturn(false);
+
+        // when
+        groupMemberWriter.deleteMember(userId, mockGroup);
+
+        // then
+        verify(groupMemberRepository).delete(mockGroupMember);
+    }
+
+    @Test
+    void deleteMember_fail_leaderCannotLeave() {
+        // given
+        Long userId = 1L;
+        Long groupId = 1L;
+        GroupErrorCode errorCode = GroupErrorCode.GROUP_LEAVE_FAIL;
+
+        given(mockGroup.getId()).willReturn(groupId);
+        given(groupMemberRepository.findByMemberIdAndGroupId(userId, groupId)).willReturn(Optional.of(mockGroupMember));
+        given(mockGroupMember.isLeader()).willReturn(true);
+
+        // when & then
+        assertThatThrownBy(() -> groupMemberWriter.deleteMember(userId, mockGroup))
+                .isInstanceOf(GroupException.class)
+                .extracting("errorCode")
+                .isEqualTo(errorCode);
+    }
 }