Add init_db script for async database initialization and extensive tests for session management

- Added `init_db.py` to handle async database initialization with the creation of the first superuser if configured.
- Introduced comprehensive tests for session management APIs, including session listing, revocation, and cleanup.
- Enhanced CRUD session logic with UUID utilities and improved error handling.

backend/tests/api/test_sessions.py

@@ -0,0 +1,367 @@
+# tests/api/test_sessions.py
+"""
+Comprehensive tests for session management API endpoints.
+"""
+import pytest
+import pytest_asyncio
+from datetime import datetime, timedelta, timezone
+from uuid import uuid4
+from unittest.mock import patch
+
+from fastapi import status
+
+from app.models.user_session import UserSession
+from app.schemas.users import UserCreate
+
+
+# Disable rate limiting for tests
+@pytest.fixture(autouse=True)
+def disable_rate_limit():
+    """Disable rate limiting for all tests in this module."""
+    with patch('app.api.routes.sessions.limiter.enabled', False):
+        yield
+
+
+@pytest_asyncio.fixture
+async def user_token(client, async_test_user):
+    """Create and return an access token for async_test_user."""
+    response = await client.post(
+        "/api/v1/auth/login",
+        json={
+            "email": "testuser@example.com",
+            "password": "TestPassword123!"
+        }
+    )
+    assert response.status_code == 200
+    return response.json()["access_token"]
+
+
+@pytest_asyncio.fixture
+async def async_test_user2(async_test_db):
+    """Create a second test user."""
+    test_engine, SessionLocal = async_test_db
+
+    async with SessionLocal() as session:
+        from app.crud.user import user as user_crud
+        from app.schemas.users import UserCreate
+
+        user_data = UserCreate(
+            email="testuser2@example.com",
+            password="TestPassword123!",
+            first_name="Test",
+            last_name="User2"
+        )
+        user = await user_crud.create(session, obj_in=user_data)
+        await session.commit()
+        await session.refresh(user)
+        return user
+
+
+class TestListMySessions:
+    """Tests for GET /api/v1/sessions/me endpoint."""
+
+    @pytest.mark.asyncio
+    async def test_list_my_sessions_success(self, client, async_test_user, async_test_db, user_token):
+        """Test successfully listing user's active sessions."""
+        test_engine, SessionLocal = async_test_db
+
+        # Create some sessions for the user
+        async with SessionLocal() as session:
+            # Active session 1
+            s1 = UserSession(
+                user_id=async_test_user.id,
+                refresh_token_jti=str(uuid4()),
+                device_name="iPhone 13",
+                ip_address="192.168.1.100",
+                user_agent="Mozilla/5.0 (iPhone)",
+                is_active=True,
+                expires_at=datetime.now(timezone.utc) + timedelta(days=7),
+                last_used_at=datetime.now(timezone.utc)
+            )
+            # Active session 2
+            s2 = UserSession(
+                user_id=async_test_user.id,
+                refresh_token_jti=str(uuid4()),
+                device_name="MacBook Pro",
+                ip_address="192.168.1.101",
+                user_agent="Mozilla/5.0 (Macintosh)",
+                is_active=True,
+                expires_at=datetime.now(timezone.utc) + timedelta(days=7),
+                last_used_at=datetime.now(timezone.utc) - timedelta(hours=1)
+            )
+            # Inactive session (should not appear)
+            s3 = UserSession(
+                user_id=async_test_user.id,
+                refresh_token_jti=str(uuid4()),
+                device_name="Old Device",
+                ip_address="192.168.1.102",
+                user_agent="Mozilla/5.0",
+                is_active=False,
+                expires_at=datetime.now(timezone.utc) + timedelta(days=7),
+                last_used_at=datetime.now(timezone.utc) - timedelta(days=1)
+            )
+            session.add_all([s1, s2, s3])
+            await session.commit()
+
+        # Make request
+        response = await client.get(
+            "/api/v1/sessions/me",
+            headers={"Authorization": f"Bearer {user_token}"}
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+        data = response.json()
+
+        assert "sessions" in data
+        assert "total" in data
+        # Note: Login creates a session, so we have 3 total (login + 2 created)
+        assert data["total"] == 3
+        assert len(data["sessions"]) == 3
+
+        # Check session data
+        device_names = {s["device_name"] for s in data["sessions"]}
+        assert "iPhone 13" in device_names
+        assert "MacBook Pro" in device_names
+        assert "Old Device" not in device_names
+
+        # First session should be marked as current
+        assert data["sessions"][0]["is_current"] is True
+
+    @pytest.mark.asyncio
+    async def test_list_my_sessions_with_login_session(self, client, async_test_user, user_token):
+        """Test listing sessions shows the login session."""
+        response = await client.get(
+            "/api/v1/sessions/me",
+            headers={"Authorization": f"Bearer {user_token}"}
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+        data = response.json()
+
+        # Login creates a session, so we should have at least 1
+        assert data["total"] >= 1
+        assert len(data["sessions"]) >= 1
+        assert data["sessions"][0]["is_current"] is True
+
+    @pytest.mark.asyncio
+    async def test_list_my_sessions_unauthorized(self, client):
+        """Test listing sessions without authentication."""
+        response = await client.get("/api/v1/sessions/me")
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+
+class TestRevokeSession:
+    """Tests for DELETE /api/v1/sessions/{session_id} endpoint."""
+
+    @pytest.mark.asyncio
+    async def test_revoke_session_success(self, client, async_test_user, async_test_db, user_token):
+        """Test successfully revoking a session."""
+        test_engine, SessionLocal = async_test_db
+
+        # Create a session to revoke
+        async with SessionLocal() as session:
+            user_session = UserSession(
+                user_id=async_test_user.id,
+                refresh_token_jti=str(uuid4()),
+                device_name="iPad",
+                ip_address="192.168.1.103",
+                user_agent="Mozilla/5.0 (iPad)",
+                is_active=True,
+                expires_at=datetime.now(timezone.utc) + timedelta(days=7),
+                last_used_at=datetime.now(timezone.utc)
+            )
+            session.add(user_session)
+            await session.commit()
+            await session.refresh(user_session)
+            session_id = user_session.id
+
+        # Revoke the session
+        response = await client.delete(
+            f"/api/v1/sessions/{session_id}",
+            headers={"Authorization": f"Bearer {user_token}"}
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+        data = response.json()
+
+        assert data["success"] is True
+        assert "iPad" in data["message"]
+
+        # Verify session is deactivated
+        async with SessionLocal() as session:
+            from app.crud.session import session as session_crud
+            revoked_session = await session_crud.get(session, id=str(session_id))
+            assert revoked_session.is_active is False
+
+    @pytest.mark.asyncio
+    async def test_revoke_session_not_found(self, client, user_token):
+        """Test revoking a non-existent session."""
+        fake_id = uuid4()
+        response = await client.delete(
+            f"/api/v1/sessions/{fake_id}",
+            headers={"Authorization": f"Bearer {user_token}"}
+        )
+
+        assert response.status_code == status.HTTP_404_NOT_FOUND
+        data = response.json()
+        assert data["success"] is False
+        assert "errors" in data
+        assert data["errors"][0]["code"] == "SYS_002"  # NOT_FOUND error code
+
+    @pytest.mark.asyncio
+    async def test_revoke_session_unauthorized(self, client, async_test_db):
+        """Test revoking a session without authentication."""
+        session_id = uuid4()
+        response = await client.delete(f"/api/v1/sessions/{session_id}")
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    @pytest.mark.asyncio
+    async def test_revoke_session_belonging_to_other_user(
+        self, client, async_test_user, async_test_user2, async_test_db, user_token
+    ):
+        """Test that users cannot revoke other users' sessions."""
+        test_engine, SessionLocal = async_test_db
+
+        # Create a session for user2
+        async with SessionLocal() as session:
+            other_user_session = UserSession(
+                user_id=async_test_user2.id,  # Different user
+                refresh_token_jti=str(uuid4()),
+                device_name="Other User Device",
+                ip_address="192.168.1.200",
+                user_agent="Mozilla/5.0",
+                is_active=True,
+                expires_at=datetime.now(timezone.utc) + timedelta(days=7),
+                last_used_at=datetime.now(timezone.utc)
+            )
+            session.add(other_user_session)
+            await session.commit()
+            await session.refresh(other_user_session)
+            session_id = other_user_session.id
+
+        # Try to revoke it as user1
+        response = await client.delete(
+            f"/api/v1/sessions/{session_id}",
+            headers={"Authorization": f"Bearer {user_token}"}
+        )
+
+        assert response.status_code == status.HTTP_403_FORBIDDEN
+        data = response.json()
+        assert data["success"] is False
+        assert "errors" in data
+        assert data["errors"][0]["code"] == "AUTH_004"  # INSUFFICIENT_PERMISSIONS
+        assert "your own sessions" in data["errors"][0]["message"].lower()
+
+
+class TestCleanupExpiredSessions:
+    """Tests for DELETE /api/v1/sessions/me/expired endpoint."""
+
+    @pytest.mark.asyncio
+    async def test_cleanup_expired_sessions_success(
+        self, client, async_test_user, async_test_db, user_token
+    ):
+        """Test successfully cleaning up expired sessions."""
+        test_engine, SessionLocal = async_test_db
+
+        # Create expired and active sessions using CRUD to avoid greenlet issues
+        from app.crud.session import session as session_crud
+        from app.schemas.sessions import SessionCreate
+
+        async with SessionLocal() as db:
+            # Expired session 1 (inactive and expired)
+            e1_data = SessionCreate(
+                user_id=async_test_user.id,
+                refresh_token_jti=str(uuid4()),
+                device_name="Expired 1",
+                ip_address="192.168.1.201",
+                user_agent="Mozilla/5.0",
+                expires_at=datetime.now(timezone.utc) - timedelta(days=1),
+                last_used_at=datetime.now(timezone.utc) - timedelta(days=2)
+            )
+            e1 = await session_crud.create_session(db, obj_in=e1_data)
+            e1.is_active = False
+            db.add(e1)
+
+            # Expired session 2 (inactive and expired)
+            e2_data = SessionCreate(
+                user_id=async_test_user.id,
+                refresh_token_jti=str(uuid4()),
+                device_name="Expired 2",
+                ip_address="192.168.1.202",
+                user_agent="Mozilla/5.0",
+                expires_at=datetime.now(timezone.utc) - timedelta(hours=1),
+                last_used_at=datetime.now(timezone.utc) - timedelta(hours=2)
+            )
+            e2 = await session_crud.create_session(db, obj_in=e2_data)
+            e2.is_active = False
+            db.add(e2)
+
+            # Active session (should not be deleted)
+            a1_data = SessionCreate(
+                user_id=async_test_user.id,
+                refresh_token_jti=str(uuid4()),
+                device_name="Active",
+                ip_address="192.168.1.203",
+                user_agent="Mozilla/5.0",
+                expires_at=datetime.now(timezone.utc) + timedelta(days=7),
+                last_used_at=datetime.now(timezone.utc)
+            )
+            await session_crud.create_session(db, obj_in=a1_data)
+            await db.commit()
+
+        # Cleanup expired sessions
+        response = await client.delete(
+            "/api/v1/sessions/me/expired",
+            headers={"Authorization": f"Bearer {user_token}"}
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+        data = response.json()
+
+        assert data["success"] is True
+        # Should have cleaned up 2 expired sessions
+        assert "2" in data["message"] or data["message"].startswith("Cleaned up 2")
+
+    @pytest.mark.asyncio
+    async def test_cleanup_expired_sessions_none_expired(
+        self, client, async_test_user, async_test_db, user_token
+    ):
+        """Test cleanup when no sessions are expired."""
+        test_engine, SessionLocal = async_test_db
+
+        # Create only active sessions using CRUD
+        from app.crud.session import session as session_crud
+        from app.schemas.sessions import SessionCreate
+
+        async with SessionLocal() as db:
+            a1_data = SessionCreate(
+                user_id=async_test_user.id,
+                refresh_token_jti=str(uuid4()),
+                device_name="Active Device",
+                ip_address="192.168.1.210",
+                user_agent="Mozilla/5.0",
+                expires_at=datetime.now(timezone.utc) + timedelta(days=7),
+                last_used_at=datetime.now(timezone.utc)
+            )
+            await session_crud.create_session(db, obj_in=a1_data)
+            await db.commit()
+
+        response = await client.delete(
+            "/api/v1/sessions/me/expired",
+            headers={"Authorization": f"Bearer {user_token}"}
+        )
+
+        assert response.status_code == status.HTTP_200_OK
+        data = response.json()
+
+        assert data["success"] is True
+        assert "0" in data["message"]
+
+    @pytest.mark.asyncio
+    async def test_cleanup_expired_sessions_unauthorized(self, client):
+        """Test cleanup without authentication."""
+        response = await client.delete("/api/v1/sessions/me/expired")
+
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED