feat(workspace): add list members use case

- Implement ListMembersUseCase to get all workspace members
- Return member info with user details (username, email, display_name)
- Show role, inviter, and join time for each member
- Only workspace members can view member list
- Add 6 comprehensive unit tests (all passed)

Phase 4 Task 18/68 completed

packages/application/workspace/__init__.py

@@ -36,6 +36,12 @@ from packages.application.workspace.list_workspaces_use_case import (
     WorkspaceInfo,
     WorkspaceDetailInfo,
 )
+from packages.application.workspace.list_members_use_case import (
+    ListMembersUseCase,
+    ListMembersRequest,
+    ListMembersResponse,
+    MemberInfo,
+)
 
 __all__ = [
     "CreateWorkspaceUseCase",
@@ -63,4 +69,8 @@ __all__ = [
     "GetWorkspaceDetailRequest",
     "WorkspaceInfo",
     "WorkspaceDetailInfo",
+    "ListMembersUseCase",
+    "ListMembersRequest",
+    "ListMembersResponse",
+    "MemberInfo",
 ]

packages/application/workspace/list_members_use_case.py

@@ -0,0 +1,117 @@
+"""
+获取成员列表 Use Case
+"""
+from typing import Optional, List
+from datetime import datetime
+
+
+class MemberInfo:
+    """成员信息"""
+    
+    def __init__(
+        self,
+        member_id: str,
+        user_id: str,
+        username: str,
+        email: str,
+        display_name: str,
+        role: str,
+        invited_by: Optional[str],
+        joined_at: datetime,
+    ):
+        self.member_id = member_id
+        self.user_id = user_id
+        self.username = username
+        self.email = email
+        self.display_name = display_name
+        self.role = role
+        self.invited_by = invited_by
+        self.joined_at = joined_at
+
+
+class ListMembersRequest:
+    """获取成员列表请求"""
+    
+    def __init__(self, workspace_id: str, requester_user_id: str):
+        self.workspace_id = workspace_id
+        self.requester_user_id = requester_user_id
+
+
+class ListMembersResponse:
+    """获取成员列表响应"""
+    
+    def __init__(self, members: List[MemberInfo]):
+        self.members = members
+
+
+class ListMembersUseCase:
+    """获取成员列表用例"""
+    
+    def __init__(
+        self,
+        workspace_repository,
+        workspace_member_repository,
+        user_repository,
+    ):
+        self.workspace_repository = workspace_repository
+        self.workspace_member_repository = workspace_member_repository
+        self.user_repository = user_repository
+    
+    def execute(self, request: ListMembersRequest) -> tuple[Optional[ListMembersResponse], Optional[str]]:
+        """
+        执行获取成员列表
+        
+        Args:
+            request: 请求
+        
+        Returns:
+            (响应, 错误信息)
+        """
+        try:
+            # 1. 验证输入
+            if not request.workspace_id:
+                return None, "Workspace ID is required"
+            
+            if not request.requester_user_id:
+                return None, "Requester user ID is required"
+            
+            # 2. 验证工作空间存在
+            workspace = self.workspace_repository.find_by_id(request.workspace_id)
+            if not workspace:
+                return None, "Workspace not found"
+            
+            # 3. 验证请求者是成员（只有成员才能查看成员列表）
+            requester_member = self.workspace_member_repository.find_by_workspace_and_user(
+                request.workspace_id,
+                request.requester_user_id,
+            )
+            if not requester_member:
+                return None, "You are not a member of this workspace"
+            
+            # 4. 获取所有成员
+            members = self.workspace_member_repository.find_by_workspace(request.workspace_id)
+            
+            # 5. 获取每个成员的用户信息
+            member_infos = []
+            for member in members:
+                user = self.user_repository.find_by_id(member.user_id)
+                if not user:
+                    continue  # 跳过不存在的用户
+                
+                member_info = MemberInfo(
+                    member_id=member.id,
+                    user_id=user.id,
+                    username=user.username,
+                    email=user.email,
+                    display_name=user.display_name,
+                    role=member.role,
+                    invited_by=member.invited_by,
+                    joined_at=member.joined_at,
+                )
+                member_infos.append(member_info)
+            
+            # 6. 返回响应
+            return ListMembersResponse(members=member_infos), None
+        
+        except Exception as e:
+            return None, f"Failed to list members: {str(e)}"

tests/unit/test_list_members_use_case.py

@@ -0,0 +1,250 @@
+"""
+获取成员列表 Use Case 测试
+"""
+import pytest
+from unittest.mock import Mock
+from datetime import datetime, timezone
+from packages.application.workspace.list_members_use_case import (
+    ListMembersUseCase,
+    ListMembersRequest,
+)
+from packages.domain.entities import (
+    Workspace,
+    WorkspaceMember,
+    WorkspaceMemberRole,
+    User,
+)
+
+
+class TestListMembersUseCase:
+    """获取成员列表测试"""
+    
+    @pytest.fixture
+    def mock_workspace_repo(self):
+        repo = Mock()
+        repo.find_by_id = Mock(return_value=None)
+        return repo
+    
+    @pytest.fixture
+    def mock_member_repo(self):
+        repo = Mock()
+        repo.find_by_workspace_and_user = Mock(return_value=None)
+        repo.find_by_workspace = Mock(return_value=[])
+        return repo
+    
+    @pytest.fixture
+    def mock_user_repo(self):
+        repo = Mock()
+        repo.find_by_id = Mock(return_value=None)
+        return repo
+    
+    @pytest.fixture
+    def use_case(self, mock_workspace_repo, mock_member_repo, mock_user_repo):
+        return ListMembersUseCase(
+            workspace_repository=mock_workspace_repo,
+            workspace_member_repository=mock_member_repo,
+            user_repository=mock_user_repo,
+        )
+    
+    @pytest.fixture
+    def test_workspace(self):
+        return Workspace(
+            id="workspace-123",
+            name="Test Workspace",
+            owner_user_id="owner-id",
+        )
+    
+    def test_list_members_success(
+        self,
+        use_case,
+        mock_workspace_repo,
+        mock_member_repo,
+        mock_user_repo,
+        test_workspace,
+    ):
+        """测试获取成员列表成功"""
+        mock_workspace_repo.find_by_id.return_value = test_workspace
+        
+        # 请求者是 Admin
+        requester_member = WorkspaceMember(
+            id="member-1",
+            workspace_id="workspace-123",
+            user_id="admin-id",
+            role=WorkspaceMemberRole.ADMIN,
+        )
+        mock_member_repo.find_by_workspace_and_user.return_value = requester_member
+        
+        # 3 个成员
+        member1 = WorkspaceMember(
+            id="member-1",
+            workspace_id="workspace-123",
+            user_id="owner-id",
+            role=WorkspaceMemberRole.OWNER,
+            invited_by=None,
+        )
+        
+        member2 = WorkspaceMember(
+            id="member-2",
+            workspace_id="workspace-123",
+            user_id="admin-id",
+            role=WorkspaceMemberRole.ADMIN,
+            invited_by="owner-id",
+        )
+        
+        member3 = WorkspaceMember(
+            id="member-3",
+            workspace_id="workspace-123",
+            user_id="user-id",
+            role=WorkspaceMemberRole.MEMBER,
+            invited_by="admin-id",
+        )
+        
+        mock_member_repo.find_by_workspace.return_value = [member1, member2, member3]
+        
+        # 用户信息
+        user1 = User(
+            id="owner-id",
+            email="owner@test.com",
+            username="owner",
+            display_name="Owner User",
+        )
+        
+        user2 = User(
+            id="admin-id",
+            email="admin@test.com",
+            username="admin",
+            display_name="Admin User",
+        )
+        
+        user3 = User(
+            id="user-id",
+            email="user@test.com",
+            username="user",
+            display_name="Regular User",
+        )
+        
+        mock_user_repo.find_by_id.side_effect = [user1, user2, user3]
+        
+        request = ListMembersRequest(
+            workspace_id="workspace-123",
+            requester_user_id="admin-id",
+        )
+        
+        response, error = use_case.execute(request)
+        
+        assert error is None
+        assert response is not None
+        assert len(response.members) == 3
+        
+        # 验证第一个成员（Owner）
+        m1 = response.members[0]
+        assert m1.user_id == "owner-id"
+        assert m1.username == "owner"
+        assert m1.email == "owner@test.com"
+        assert m1.role == "owner"
+        assert m1.invited_by is None
+        
+        # 验证第二个成员（Admin）
+        m2 = response.members[1]
+        assert m2.user_id == "admin-id"
+        assert m2.role == "admin"
+        assert m2.invited_by == "owner-id"
+        
+        # 验证第三个成员（Member）
+        m3 = response.members[2]
+        assert m3.user_id == "user-id"
+        assert m3.role == "member"
+        assert m3.invited_by == "admin-id"
+    
+    def test_list_members_workspace_not_found(
+        self,
+        use_case,
+        mock_workspace_repo,
+    ):
+        """测试工作空间不存在"""
+        mock_workspace_repo.find_by_id.return_value = None
+        
+        request = ListMembersRequest(
+            workspace_id="nonexistent",
+            requester_user_id="user-id",
+        )
+        
+        response, error = use_case.execute(request)
+        
+        assert response is None
+        assert error == "Workspace not found"
+    
+    def test_list_members_requester_not_member(
+        self,
+        use_case,
+        mock_workspace_repo,
+        mock_member_repo,
+        test_workspace,
+    ):
+        """测试请求者不是成员"""
+        mock_workspace_repo.find_by_id.return_value = test_workspace
+        mock_member_repo.find_by_workspace_and_user.return_value = None
+        
+        request = ListMembersRequest(
+            workspace_id="workspace-123",
+            requester_user_id="outsider-id",
+        )
+        
+        response, error = use_case.execute(request)
+        
+        assert response is None
+        assert error == "You are not a member of this workspace"
+    
+    def test_list_members_empty_workspace(
+        self,
+        use_case,
+        mock_workspace_repo,
+        mock_member_repo,
+        test_workspace,
+    ):
+        """测试空工作空间（理论上不应该发生）"""
+        mock_workspace_repo.find_by_id.return_value = test_workspace
+        
+        requester_member = WorkspaceMember(
+            id="member-1",
+            workspace_id="workspace-123",
+            user_id="user-id",
+            role=WorkspaceMemberRole.MEMBER,
+        )
+        mock_member_repo.find_by_workspace_and_user.return_value = requester_member
+        mock_member_repo.find_by_workspace.return_value = []
+        
+        request = ListMembersRequest(
+            workspace_id="workspace-123",
+            requester_user_id="user-id",
+        )
+        
+        response, error = use_case.execute(request)
+        
+        assert error is None
+        assert response is not None
+        assert len(response.members) == 0
+    
+    def test_list_members_missing_workspace_id(self, use_case):
+        """测试缺少工作空间 ID"""
+        request = ListMembersRequest(
+            workspace_id="",
+            requester_user_id="user-id",
+        )
+        
+        response, error = use_case.execute(request)
+        
+        assert response is None
+        assert error == "Workspace ID is required"
+    
+    def test_list_members_missing_requester_id(self, use_case):
+        """测试缺少请求者 ID"""
+        request = ListMembersRequest(
+            workspace_id="workspace-123",
+            requester_user_id="",
+        )
+        
+        response, error = use_case.execute(request)
+        
+        assert response is None
+        assert error == "Requester user ID is required"