✨ Feat: 그룹 소속 유저 조회 기능

src/main/java/slvtwn/khu/toyouserver/application/GroupService.java

@@ -1,38 +1,31 @@
 package slvtwn.khu.toyouserver.application;
 
+import java.util.List;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
-import slvtwn.khu.toyouserver.common.ErrorType;
 import slvtwn.khu.toyouserver.domain.Group;
 import slvtwn.khu.toyouserver.domain.MemberRepository;
-import slvtwn.khu.toyouserver.domain.User;
 import slvtwn.khu.toyouserver.dto.GroupResponse;
-import slvtwn.khu.toyouserver.exception.ToyouException;
 import slvtwn.khu.toyouserver.persistance.GroupRepository;
-import slvtwn.khu.toyouserver.persistance.UserRepository;
 
 @Service
-@Transactional(readOnly = true)
 public class GroupService {
 
 	private final GroupRepository groupRepository;
-	private final UserRepository userRepository;
 	private final MemberRepository memberRepository;
+	private final MemberService memberService;
 
-	public GroupService(GroupRepository groupRepository, UserRepository userRepository,
-	                    MemberRepository memberRepository) {
+	public GroupService(GroupRepository groupRepository,
+	                    MemberRepository memberRepository, MemberService memberService) {
 		this.groupRepository = groupRepository;
-		this.userRepository = userRepository;
 		this.memberRepository = memberRepository;
+		this.memberService = memberService;
 	}
 
 	@Transactional
 	public GroupResponse registerUser(long groupId, long userId) {
-		Group group = groupRepository.findById(groupId)
-				.orElseThrow(() -> new ToyouException(ErrorType.GROUP_NOT_FOUND));
-		User user = userRepository.findById(userId)
-				.orElseThrow(() -> new ToyouException(ErrorType.USER_NOT_FOUND));
-		return new GroupResponse(group.getId(), group.getName());
+		Group savedGroup = memberService.registerMember(groupId, userId).getGroup();
+		return new GroupResponse(savedGroup.getId(), savedGroup.getName());
 	}
 
 	@Transactional
@@ -41,4 +34,12 @@ public GroupResponse create(String name) {
 		Group savedGroup = groupRepository.save(group);
 		return new GroupResponse(savedGroup.getId(), savedGroup.getName());
 	}
+
+	@Transactional(readOnly = true)
+	public List<GroupResponse> findRegisteredGroups(long userId) {
+		List<Group> groups = memberRepository.findGroupsByUserId(userId);
+		return groups.stream()
+				.map(group -> new GroupResponse(group.getId(), group.getName()))
+				.toList();
+	}
 }

src/main/java/slvtwn/khu/toyouserver/application/MemberService.java

@@ -0,0 +1,35 @@
+package slvtwn.khu.toyouserver.application;
+
+import org.springframework.stereotype.Service;
+import slvtwn.khu.toyouserver.common.ErrorType;
+import slvtwn.khu.toyouserver.domain.Group;
+import slvtwn.khu.toyouserver.domain.Member;
+import slvtwn.khu.toyouserver.domain.MemberRepository;
+import slvtwn.khu.toyouserver.domain.User;
+import slvtwn.khu.toyouserver.exception.ToyouException;
+import slvtwn.khu.toyouserver.persistance.GroupRepository;
+import slvtwn.khu.toyouserver.persistance.UserRepository;
+
+@Service
+public class MemberService {
+
+	private final UserRepository userRepository;
+	private final MemberRepository memberRepository;
+	private final GroupRepository groupRepository;
+
+
+	public MemberService(GroupRepository groupRepository, UserRepository userRepository,
+	                     MemberRepository memberRepository) {
+		this.groupRepository = groupRepository;
+		this.userRepository = userRepository;
+		this.memberRepository = memberRepository;
+	}
+
+	public Member registerMember(long groupId, long userId) {
+		Group group = groupRepository.findById(groupId)
+				.orElseThrow(() -> new ToyouException(ErrorType.GROUP_NOT_FOUND));
+		User user = userRepository.findById(userId)
+				.orElseThrow(() -> new ToyouException(ErrorType.USER_NOT_FOUND));
+		return memberRepository.save(new Member(user, group));
+	}
+}

src/main/java/slvtwn/khu/toyouserver/domain/Member.java

@@ -16,19 +16,24 @@
 @Getter
 public class Member extends BaseTimeEntity {
 
-    @Id
-    @GeneratedValue
-    private Long id;
+	@Id
+	@GeneratedValue
+	private Long id;
 
-    @ManyToOne(fetch = FetchType.LAZY)
-    @JoinColumn(name = "user_id")
-    private User user;
+	@ManyToOne(fetch = FetchType.LAZY)
+	@JoinColumn(name = "user_id")
+	private User user;
 
-    @ManyToOne(fetch = FetchType.LAZY)
-    @JoinColumn(name = "group_id")
-    private Group group;
+	@ManyToOne(fetch = FetchType.LAZY)
+	@JoinColumn(name = "group_id")
+	private Group group;
 
-    public Member(Group group) {
-        this.group = group;
-    }
+	public Member(Group group) {
+		this.group = group;
+	}
+
+	public Member(User user, Group group) {
+		this.user = user;
+		this.group = group;
+	}
 }

src/main/java/slvtwn/khu/toyouserver/domain/MemberRepository.java

@@ -2,9 +2,13 @@
 
 import java.util.List;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
 import org.springframework.stereotype.Repository;
 
 @Repository
 public interface MemberRepository extends JpaRepository<Member, Long> {
 	List<Member> findByGroupId(Long groupId);
+
+	@Query("SELECT m.group FROM Member m WHERE m.user.id = :userId")
+	List<Group> findGroupsByUserId(Long userId);
 }

src/main/java/slvtwn/khu/toyouserver/domain/SessionUser.java

@@ -3,12 +3,14 @@
 import jakarta.persistence.Column;
 import jakarta.persistence.Entity;
 import jakarta.persistence.Id;
+import jakarta.persistence.Table;
 import lombok.AccessLevel;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
 import slvtwn.khu.toyouserver.common.BaseTimeEntity;
 
 @Entity
+@Table(name = "session_users")
 @NoArgsConstructor(access = AccessLevel.PROTECTED)
 @Getter
 public class SessionUser extends BaseTimeEntity {
@@ -20,6 +22,8 @@ public class SessionUser extends BaseTimeEntity {
 	@Column(name = "user_id", nullable = false)
 	private Long userId;
 
+	// TODO ; 카드
+
 	public SessionUser(String sessionId, Long userId) {
 		this.sessionId = sessionId;
 		this.userId = userId;

src/main/java/slvtwn/khu/toyouserver/presentation/GroupController.java

@@ -8,6 +8,8 @@
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RestController;
 import slvtwn.khu.toyouserver.application.GroupService;
+import slvtwn.khu.toyouserver.common.UserAuthentication;
+import slvtwn.khu.toyouserver.domain.User;
 import slvtwn.khu.toyouserver.dto.GroupCreateRequest;
 import slvtwn.khu.toyouserver.dto.GroupResponse;
 
@@ -17,13 +19,18 @@ public class GroupController {
 
 	private final GroupService groupService;
 
-	@PostMapping("/groups/create")
+	@PostMapping("/groups")
 	public GroupResponse createGroup(@RequestBody GroupCreateRequest request) {
 		return groupService.create(request.name());
 	}
-  
+
 	@PostMapping("/groups/{groupId}/members")
 	public GroupResponse registerMember(@PathVariable long groupId) {
 		return groupService.registerUser(groupId, 1L); // TODO: user -> argumentResolver 등록 필요
 	}
+
+	@GetMapping("/groups")
+	public List<GroupResponse> findRegisteredGroups(@UserAuthentication User user) {
+		return groupService.findRegisteredGroups(user.getId());
+	}
 }

src/test/java/slvtwn/khu/toyouserver/application/GroupServiceTest.java

@@ -0,0 +1,73 @@
+package slvtwn.khu.toyouserver.application;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.time.LocalDate;
+import java.util.List;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import slvtwn.khu.toyouserver.domain.Group;
+import slvtwn.khu.toyouserver.domain.User;
+import slvtwn.khu.toyouserver.dto.GroupResponse;
+import slvtwn.khu.toyouserver.persistance.GroupRepository;
+import slvtwn.khu.toyouserver.persistance.UserRepository;
+
+@SpringBootTest
+class GroupServiceTest {
+
+	@Autowired
+	GroupRepository groupRepository;
+
+	@Autowired
+	UserRepository userRepository;
+
+	@Autowired
+	GroupService groupService;
+
+	@DisplayName("그룹은 이름을 필수로 가진다.")
+	@Test
+	void 그룹은_이름으로_생성된다() {
+		String groupName = "Name Created Group";
+		Group group = new Group(groupName);
+		groupRepository.save(group);
+
+		GroupResponse groupResponse = groupService.create(groupName);
+		assertThat(groupResponse.name()).isEqualTo(groupName);
+	}
+
+	@DisplayName("사용자는 그룹에 가입한다.")
+	@Test
+	void 사용자는_그룹에_가입한다() {
+		Group group = new Group("Group");
+		groupRepository.save(group);
+		User user = new User("Hart", LocalDate.now(), "www.profile-picture.com");
+		userRepository.save(user);
+
+		GroupResponse groupResponse = groupService.registerUser(group.getId(), 1L);
+
+		assertThat(groupResponse.id()).isEqualTo(group.getId());
+		assertThat(groupResponse.name()).isEqualTo(group.getName());
+	}
+
+	@DisplayName("사용자는 가입한 그룹을 조회한다.")
+	@Test
+	void 사용자별_그룹을_조회한다() {
+		Group group1 = new Group("Group-1"), group2 = new Group("Group-2");
+		groupRepository.save(group1);
+		groupRepository.save(group2);
+
+		User user = new User("Hart", LocalDate.now(), "www.profile-picture.com");
+		userRepository.save(user);
+
+		groupService.registerUser(group1.getId(), user.getId());
+		groupService.registerUser(group2.getId(), user.getId());
+
+		List<GroupResponse> groups = groupService.findRegisteredGroups(user.getId());
+
+		assertThat(groups).hasSize(2);
+		assertThat(groups.get(0).name()).isEqualTo(group1.getName());
+		assertThat(groups.get(1).name()).isEqualTo(group2.getName());
+	}
+}