From 58f9ad72ed8e471a0589c4cea1aa432930b7ead0 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sun, 5 Apr 2026 15:10:38 +0000
Subject: [PATCH] test: add 150 new unit tests covering auth, users,
 notifications, logs, settings, GDPR, and Gmail label utilities

Agent-Logs-Url: https://github.com/christianlouis/InboxConverge/sessions/8cb47b1c-b744-4212-8b6d-8132d6642d98

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>
---
 CHANGELOG.md                                  |   6 +
 .../tests/unit/test_app_settings_endpoints.py | 241 ++++++++++++
 backend/tests/unit/test_auth_endpoints.py     | 369 ++++++++++++++++++
 backend/tests/unit/test_auth_service.py       | 192 +++++++++
 backend/tests/unit/test_gdpr.py               | 102 +++++
 backend/tests/unit/test_gmail_labels.py       | 184 +++++++++
 backend/tests/unit/test_logs_endpoints.py     | 335 ++++++++++++++++
 .../tests/unit/test_notification_service.py   | 215 ++++++++++
 .../unit/test_notifications_endpoints.py      | 278 +++++++++++++
 backend/tests/unit/test_users_endpoints.py    | 247 ++++++++++++
 backend/tests/unit/test_version_endpoint.py   |  42 ++
 docs/TODO.md                                  |   2 +
 12 files changed, 2213 insertions(+)
 create mode 100644 backend/tests/unit/test_app_settings_endpoints.py
 create mode 100644 backend/tests/unit/test_auth_endpoints.py
 create mode 100644 backend/tests/unit/test_auth_service.py
 create mode 100644 backend/tests/unit/test_gdpr.py
 create mode 100644 backend/tests/unit/test_gmail_labels.py
 create mode 100644 backend/tests/unit/test_logs_endpoints.py
 create mode 100644 backend/tests/unit/test_notification_service.py
 create mode 100644 backend/tests/unit/test_notifications_endpoints.py
 create mode 100644 backend/tests/unit/test_users_endpoints.py
 create mode 100644 backend/tests/unit/test_version_endpoint.py

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 90d014c..15d4dab 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 <!-- version list -->
 
+## [Unreleased]
+
+### Added
+
+- **Backend test coverage expanded** (+150 tests, 361 → 511 total): added `test_gdpr.py` (GDPR masking utilities), `test_gmail_labels.py` (Gmail label helpers), `test_notification_service.py` (Apprise notification service), `test_auth_service.py` (OAuth service token exchange and token creation), `test_version_endpoint.py`, `test_auth_endpoints.py` (register, login, Google OAuth, authorize-url, domain helpers), `test_users_endpoints.py` (profile CRUD, SMTP config upsert/delete), `test_notifications_endpoints.py` (full CRUD + test-send), `test_logs_endpoints.py` (processing-runs pagination/filtering + run log retrieval), and `test_app_settings_endpoints.py` (list, upsert, delete, seed-defaults with bootstrap key guards).
+
 ## v0.6.0 (2026-03-29)
 
 ### Chores
diff --git a/backend/tests/unit/test_app_settings_endpoints.py b/backend/tests/unit/test_app_settings_endpoints.py
new file mode 100644
index 0000000..51c244a
--- /dev/null
+++ b/backend/tests/unit/test_app_settings_endpoints.py
@@ -0,0 +1,241 @@
+"""
+Unit tests for app settings endpoints (api/v1/endpoints/app_settings.py).
+
+All database interactions and auth dependencies are mocked.
+"""
+
+import pytest
+from datetime import datetime, timezone
+from unittest.mock import AsyncMock, MagicMock, patch
+
+from httpx import AsyncClient, ASGITransport
+
+from app.main import create_application
+from app.core.database import get_db
+from app.core.deps import get_current_superuser, get_current_user
+from app.models.database_models import User, SubscriptionTier
+
+# ── helpers ──────────────────────────────────────────────────────────────────
+
+
+def _make_admin_user(**overrides) -> MagicMock:
+    defaults = dict(
+        id=1,
+        email="admin@example.com",
+        full_name="Admin",
+        is_active=True,
+        is_superuser=True,
+        subscription_tier=SubscriptionTier.FREE,
+        subscription_status="active",
+        google_id=None,
+        oauth_provider=None,
+        last_login_at=None,
+        created_at=datetime.now(timezone.utc),
+        updated_at=datetime.now(timezone.utc),
+        stripe_customer_id=None,
+        stripe_subscription_id=None,
+        subscription_expires_at=None,
+    )
+    defaults.update(overrides)
+    u = MagicMock(spec=User)
+    for k, v in defaults.items():
+        setattr(u, k, v)
+    return u
+
+
+def _make_setting(**overrides) -> MagicMock:
+    defaults = dict(
+        id=1,
+        key="SOME_SETTING",
+        value="some_value",
+        value_type="string",
+        description="A setting",
+        is_secret=False,
+        category="general",
+    )
+    defaults.update(overrides)
+    s = MagicMock()
+    for k, v in defaults.items():
+        setattr(s, k, v)
+    return s
+
+
+@pytest.fixture
+def app():
+    return create_application()
+
+
+@pytest.fixture
+def mock_db():
+    db = AsyncMock()
+    db.commit = AsyncMock()
+    db.refresh = AsyncMock()
+    db.add = MagicMock()
+    db.delete = AsyncMock()
+    return db
+
+
+@pytest.fixture
+def admin_user():
+    return _make_admin_user()
+
+
+@pytest.fixture
+async def admin_client(app, admin_user, mock_db):
+    async def _override_superuser():
+        return admin_user
+
+    async def _override_db():
+        yield mock_db
+
+    app.dependency_overrides[get_current_superuser] = _override_superuser
+    app.dependency_overrides[get_current_user] = _override_superuser
+    app.dependency_overrides[get_db] = _override_db
+
+    transport = ASGITransport(app=app)
+    async with AsyncClient(transport=transport, base_url="http://test") as client:
+        yield client
+
+    app.dependency_overrides.clear()
+
+
+# ── GET /app-settings ─────────────────────────────────────────────────────────
+
+
+class TestListSettings:
+    async def test_returns_list(self, admin_client):
+        setting = _make_setting()
+        with patch(
+            "app.api.v1.endpoints.app_settings.ConfigService.list_all",
+            new=AsyncMock(return_value=[setting]),
+        ):
+            response = await admin_client.get("/api/v1/settings")
+        assert response.status_code == 200
+        data = response.json()
+        assert isinstance(data, list)
+        assert len(data) == 1
+        assert data[0]["key"] == "SOME_SETTING"
+        assert data[0]["value"] == "some_value"
+
+    async def test_secret_value_masked(self, admin_client):
+        setting = _make_setting(key="SECRET_KEY", value="supersecret", is_secret=True)
+        with patch(
+            "app.api.v1.endpoints.app_settings.ConfigService.list_all",
+            new=AsyncMock(return_value=[setting]),
+        ):
+            response = await admin_client.get("/api/v1/settings")
+        assert response.status_code == 200
+        data = response.json()
+        assert data[0]["value"] == "********"
+
+    async def test_filters_by_category(self, admin_client):
+        with patch(
+            "app.api.v1.endpoints.app_settings.ConfigService.list_all",
+            new=AsyncMock(return_value=[]),
+        ):
+            response = await admin_client.get("/api/v1/settings?category=general")
+        assert response.status_code == 200
+
+    async def test_unauthenticated_401(self, app):
+        transport = ASGITransport(app=app)
+        async with AsyncClient(transport=transport, base_url="http://test") as client:
+            response = await client.get("/api/v1/settings")
+        assert response.status_code == 401
+
+
+# ── PUT /app-settings/{key} ───────────────────────────────────────────────────
+
+
+class TestUpsertSetting:
+    async def test_upsert_creates_or_updates(self, admin_client):
+        setting = _make_setting(key="MY_KEY", value="myval")
+        with patch(
+            "app.api.v1.endpoints.app_settings.ConfigService.set",
+            new=AsyncMock(return_value=setting),
+        ):
+            response = await admin_client.put(
+                "/api/v1/settings/MY_KEY",
+                json={
+                    "key": "MY_KEY",
+                    "value": "myval",
+                    "value_type": "string",
+                    "is_secret": False,
+                },
+            )
+        assert response.status_code == 200
+        data = response.json()
+        assert data["key"] == "MY_KEY"
+        assert data["value"] == "myval"
+
+    async def test_bootstrap_key_rejected_400(self, admin_client):
+        response = await admin_client.put(
+            "/api/v1/settings/SECRET_KEY",
+            json={"key": "SECRET_KEY", "value": "new_secret"},
+        )
+        assert response.status_code == 400
+        assert "bootstrap" in response.json()["detail"].lower()
+
+    async def test_database_url_rejected(self, admin_client):
+        response = await admin_client.put(
+            "/api/v1/settings/DATABASE_URL",
+            json={"key": "DATABASE_URL", "value": "postgresql://..."},
+        )
+        assert response.status_code == 400
+
+    async def test_secret_value_masked_in_response(self, admin_client):
+        setting = _make_setting(key="API_KEY", value="secret!", is_secret=True)
+        with patch(
+            "app.api.v1.endpoints.app_settings.ConfigService.set",
+            new=AsyncMock(return_value=setting),
+        ):
+            response = await admin_client.put(
+                "/api/v1/settings/API_KEY",
+                json={
+                    "key": "API_KEY",
+                    "value": "secret!",
+                    "is_secret": True,
+                },
+            )
+        assert response.status_code == 200
+        assert response.json()["value"] == "********"
+
+
+# ── DELETE /app-settings/{key} ────────────────────────────────────────────────
+
+
+class TestDeleteSetting:
+    async def test_deletes_existing_setting(self, admin_client):
+        with patch(
+            "app.api.v1.endpoints.app_settings.ConfigService.delete",
+            new=AsyncMock(return_value=True),
+        ):
+            response = await admin_client.delete("/api/v1/settings/MY_KEY")
+        assert response.status_code == 204
+
+    async def test_404_when_not_found(self, admin_client):
+        with patch(
+            "app.api.v1.endpoints.app_settings.ConfigService.delete",
+            new=AsyncMock(return_value=False),
+        ):
+            response = await admin_client.delete("/api/v1/settings/MISSING_KEY")
+        assert response.status_code == 404
+
+    async def test_bootstrap_key_rejected_400(self, admin_client):
+        response = await admin_client.delete("/api/v1/settings/SECRET_KEY")
+        assert response.status_code == 400
+
+
+# ── POST /app-settings/seed-defaults ─────────────────────────────────────────
+
+
+class TestSeedDefaultSettings:
+    async def test_seeds_defaults(self, admin_client):
+        with patch(
+            "app.api.v1.endpoints.app_settings.ConfigService.seed_defaults",
+            new=AsyncMock(return_value=5),
+        ):
+            response = await admin_client.post("/api/v1/settings/seed-defaults")
+        assert response.status_code == 200
+        data = response.json()
+        assert data["created"] == 5
+        assert "Seeded 5" in data["message"]
diff --git a/backend/tests/unit/test_auth_endpoints.py b/backend/tests/unit/test_auth_endpoints.py
new file mode 100644
index 0000000..ffc2c6d
--- /dev/null
+++ b/backend/tests/unit/test_auth_endpoints.py
@@ -0,0 +1,369 @@
+"""
+Unit tests for authentication endpoints (api/v1/endpoints/auth.py).
+
+All database interactions and the oauth_service are mocked so no real
+PostgreSQL instance or Google credentials are needed.
+"""
+
+import pytest
+from datetime import datetime, timezone
+from unittest.mock import AsyncMock, MagicMock, patch
+
+from httpx import AsyncClient, ASGITransport
+
+from app.main import create_application
+from app.core.database import get_db
+from app.models.database_models import User, SubscriptionTier
+
+# ── helpers ──────────────────────────────────────────────────────────────────
+
+
+def _make_user(**overrides) -> MagicMock:
+    defaults = dict(
+        id=1,
+        email="user@example.com",
+        hashed_password=None,
+        full_name="Test User",
+        is_active=True,
+        is_superuser=False,
+        subscription_tier=SubscriptionTier.FREE,
+        subscription_status="active",
+        google_id=None,
+        oauth_provider=None,
+        last_login_at=None,
+        created_at=datetime.now(timezone.utc),
+        updated_at=datetime.now(timezone.utc),
+        stripe_customer_id=None,
+        stripe_subscription_id=None,
+        subscription_expires_at=None,
+    )
+    defaults.update(overrides)
+    u = MagicMock(spec=User)
+    for k, v in defaults.items():
+        setattr(u, k, v)
+    return u
+
+
+def _scalar_one_or_none(value):
+    r = MagicMock()
+    r.scalar_one_or_none.return_value = value
+    return r
+
+
+@pytest.fixture
+def app():
+    return create_application()
+
+
+@pytest.fixture
+def mock_db():
+    db = AsyncMock()
+    db.commit = AsyncMock()
+    db.refresh = AsyncMock()
+    db.add = MagicMock()
+    return db
+
+
+@pytest.fixture
+async def anon_client(app, mock_db):
+    """Client with no auth (db mocked)."""
+
+    async def _override_db():
+        yield mock_db
+
+    app.dependency_overrides[get_db] = _override_db
+    transport = ASGITransport(app=app)
+    async with AsyncClient(transport=transport, base_url="http://test") as client:
+        yield client
+    app.dependency_overrides.clear()
+
+
+# ── /register ─────────────────────────────────────────────────────────────────
+
+
+class TestRegisterEndpoint:
+    async def test_register_new_user_201(self, anon_client, mock_db):
+        # DB returns no existing user
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(None))
+
+        # db.refresh will be called with the new User object; we simulate it
+        # by setting the required response fields on that object.
+        from datetime import datetime, timezone
+        from app.models.database_models import SubscriptionTier
+
+        async def _refresh(obj):
+            obj.id = 99
+            obj.email = "new@example.com"
+            obj.full_name = None
+            obj.is_active = True
+            obj.subscription_tier = SubscriptionTier.FREE
+            obj.subscription_status = "active"
+            obj.created_at = datetime.now(timezone.utc)
+            obj.updated_at = datetime.now(timezone.utc)
+
+        mock_db.refresh = AsyncMock(side_effect=_refresh)
+
+        response = await anon_client.post(
+            "/api/v1/auth/register",
+            json={"email": "new@example.com", "password": "secretpassword"},
+        )
+        assert response.status_code == 201
+
+    async def test_register_existing_user_400(self, anon_client, mock_db):
+        existing = _make_user(email="taken@example.com")
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(existing))
+
+        response = await anon_client.post(
+            "/api/v1/auth/register",
+            json={"email": "taken@example.com", "password": "pass"},
+        )
+        assert response.status_code == 400
+        assert "already registered" in response.json()["detail"]
+
+    async def test_register_blocked_domain_403(self, app, mock_db):
+        """When ALLOWED_DOMAINS is set, unknown domains should get 403."""
+
+        async def _override_db():
+            yield mock_db
+
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(None))
+        app.dependency_overrides[get_db] = _override_db
+
+        transport = ASGITransport(app=app)
+        with patch("app.api.v1.endpoints.auth.settings") as mock_settings:
+            mock_settings.ALLOWED_DOMAINS = ["allowed.com"]
+            mock_settings.DEFAULT_USER_TIER = "free"
+            mock_settings.ADMIN_EMAIL = None
+            async with AsyncClient(
+                transport=transport, base_url="http://test"
+            ) as client:
+                response = await client.post(
+                    "/api/v1/auth/register",
+                    json={"email": "user@blocked.com", "password": "pass"},
+                )
+        app.dependency_overrides.clear()
+        assert response.status_code == 403
+
+
+# ── /login ─────────────────────────────────────────────────────────────────────
+
+
+class TestLoginEndpoint:
+    async def test_login_success_returns_tokens(self, anon_client, mock_db):
+        from app.core.security import get_password_hash
+
+        hashed = get_password_hash("correctpassword")
+        user = _make_user(email="user@example.com", hashed_password=hashed)
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(user))
+
+        response = await anon_client.post(
+            "/api/v1/auth/login",
+            data={"username": "user@example.com", "password": "correctpassword"},
+        )
+        assert response.status_code == 200
+        data = response.json()
+        assert "access_token" in data
+        assert "refresh_token" in data
+        assert data["token_type"] == "bearer"
+
+    async def test_login_wrong_password_401(self, anon_client, mock_db):
+        from app.core.security import get_password_hash
+
+        hashed = get_password_hash("correctpassword")
+        user = _make_user(email="user@example.com", hashed_password=hashed)
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(user))
+
+        response = await anon_client.post(
+            "/api/v1/auth/login",
+            data={"username": "user@example.com", "password": "wrongpassword"},
+        )
+        assert response.status_code == 401
+
+    async def test_login_user_not_found_401(self, anon_client, mock_db):
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(None))
+
+        response = await anon_client.post(
+            "/api/v1/auth/login",
+            data={"username": "unknown@example.com", "password": "pass"},
+        )
+        assert response.status_code == 401
+
+    async def test_login_inactive_user_403(self, anon_client, mock_db):
+        from app.core.security import get_password_hash
+
+        hashed = get_password_hash("password")
+        user = _make_user(
+            email="user@example.com", hashed_password=hashed, is_active=False
+        )
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(user))
+
+        response = await anon_client.post(
+            "/api/v1/auth/login",
+            data={"username": "user@example.com", "password": "password"},
+        )
+        assert response.status_code == 403
+
+    async def test_login_no_password_hash_401(self, anon_client, mock_db):
+        """OAuth-only users have no hashed_password – login should fail."""
+        user = _make_user(hashed_password=None)
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(user))
+
+        response = await anon_client.post(
+            "/api/v1/auth/login",
+            data={"username": "user@example.com", "password": "pass"},
+        )
+        assert response.status_code == 401
+
+
+# ── /google ────────────────────────────────────────────────────────────────────
+
+
+class TestGoogleOAuthEndpoint:
+    async def test_google_oauth_unverified_email_400(self, anon_client, mock_db):
+        with patch(
+            "app.api.v1.endpoints.auth.oauth_service.get_google_user_info",
+            new=AsyncMock(
+                return_value={
+                    "email": "user@gmail.com",
+                    "google_id": "g123",
+                    "full_name": "Test",
+                    "verified_email": False,
+                }
+            ),
+        ):
+            response = await anon_client.post(
+                "/api/v1/auth/google",
+                json={"code": "code", "redirect_uri": "http://localhost"},
+            )
+        assert response.status_code == 400
+
+    async def test_google_oauth_new_user_created(self, anon_client, mock_db):
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(None))
+        mock_db.refresh = AsyncMock(side_effect=lambda obj: None)
+
+        with (
+            patch(
+                "app.api.v1.endpoints.auth.oauth_service.get_google_user_info",
+                new=AsyncMock(
+                    return_value={
+                        "email": "google@example.com",
+                        "google_id": "g123",
+                        "full_name": "Google User",
+                        "verified_email": True,
+                    }
+                ),
+            ),
+            patch(
+                "app.api.v1.endpoints.auth.oauth_service.create_tokens_for_user",
+                return_value={
+                    "access_token": "tok",
+                    "refresh_token": "ref",
+                    "token_type": "bearer",
+                },
+            ),
+        ):
+            response = await anon_client.post(
+                "/api/v1/auth/google",
+                json={"code": "code", "redirect_uri": "http://localhost"},
+            )
+        assert response.status_code == 200
+        assert response.json()["access_token"] == "tok"
+
+    async def test_google_oauth_existing_user_logs_in(self, anon_client, mock_db):
+        existing = _make_user(email="google@example.com", google_id="g123")
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(existing))
+        mock_db.refresh = AsyncMock(side_effect=lambda obj: None)
+
+        with (
+            patch(
+                "app.api.v1.endpoints.auth.oauth_service.get_google_user_info",
+                new=AsyncMock(
+                    return_value={
+                        "email": "google@example.com",
+                        "google_id": "g123",
+                        "full_name": "Google User",
+                        "verified_email": True,
+                    }
+                ),
+            ),
+            patch(
+                "app.api.v1.endpoints.auth.oauth_service.create_tokens_for_user",
+                return_value={
+                    "access_token": "tok2",
+                    "refresh_token": "ref2",
+                    "token_type": "bearer",
+                },
+            ),
+        ):
+            response = await anon_client.post(
+                "/api/v1/auth/google",
+                json={"code": "code", "redirect_uri": "http://localhost"},
+            )
+        assert response.status_code == 200
+
+
+# ── /google/authorize-url ──────────────────────────────────────────────────────
+
+
+class TestGoogleAuthorizeUrl:
+    async def test_returns_authorization_url(self, anon_client):
+        response = await anon_client.get(
+            "/api/v1/auth/google/authorize-url",
+            params={"redirect_uri": "http://localhost/callback"},
+        )
+        assert response.status_code == 200
+        data = response.json()
+        assert "authorization_url" in data
+        assert "accounts.google.com" in data["authorization_url"]
+
+    async def test_url_contains_redirect_uri(self, anon_client):
+        redirect = "http://myapp.example.com/callback"
+        response = await anon_client.get(
+            "/api/v1/auth/google/authorize-url",
+            params={"redirect_uri": redirect},
+        )
+        assert response.status_code == 200
+
+
+# ── helper functions (domain checks, tier, admin email) ───────────────────────
+
+
+class TestAuthHelpers:
+    def test_domain_of(self):
+        from app.api.v1.endpoints.auth import _domain_of
+
+        assert _domain_of("user@Example.COM") == "example.com"
+        assert _domain_of("a@b.de") == "b.de"
+
+    def test_default_tier_fallback(self):
+        from app.api.v1.endpoints.auth import _default_tier
+        from app.models.database_models import SubscriptionTier
+
+        with patch("app.api.v1.endpoints.auth.settings") as ms:
+            ms.DEFAULT_USER_TIER = "invalid_tier"
+            tier = _default_tier()
+        assert tier == SubscriptionTier.FREE
+
+    def test_default_tier_valid(self):
+        from app.api.v1.endpoints.auth import _default_tier
+        from app.models.database_models import SubscriptionTier
+
+        with patch("app.api.v1.endpoints.auth.settings") as ms:
+            ms.DEFAULT_USER_TIER = "pro"
+            tier = _default_tier()
+        assert tier == SubscriptionTier.PRO
+
+    def test_is_admin_email_match(self):
+        from app.api.v1.endpoints.auth import _is_admin_email
+
+        with patch("app.api.v1.endpoints.auth.settings") as ms:
+            ms.ADMIN_EMAIL = "admin@example.com"
+            assert _is_admin_email("ADMIN@EXAMPLE.COM") is True
+            assert _is_admin_email("other@example.com") is False
+
+    def test_is_admin_email_none_config(self):
+        from app.api.v1.endpoints.auth import _is_admin_email
+
+        with patch("app.api.v1.endpoints.auth.settings") as ms:
+            ms.ADMIN_EMAIL = None
+            assert _is_admin_email("admin@example.com") is False
diff --git a/backend/tests/unit/test_auth_service.py b/backend/tests/unit/test_auth_service.py
new file mode 100644
index 0000000..71270ee
--- /dev/null
+++ b/backend/tests/unit/test_auth_service.py
@@ -0,0 +1,192 @@
+"""
+Unit tests for the OAuth / auth service (services/auth_service.py).
+
+External HTTP calls are mocked via httpx.  No real network or DB needed.
+"""
+
+import pytest
+from unittest.mock import AsyncMock, MagicMock, patch
+
+from fastapi import HTTPException
+
+from app.services.auth_service import OAuthService
+from app.models.database_models import User
+
+# ── helpers ──────────────────────────────────────────────────────────────────
+
+
+def _make_user(id: int = 1, email: str = "user@example.com") -> MagicMock:
+    u = MagicMock(spec=User)
+    u.id = id
+    u.email = email
+    return u
+
+
+def _mock_token_response(
+    access_token: str = "access123", refresh_token: str = "refresh456"
+):
+    resp = MagicMock()
+    resp.status_code = 200
+    resp.json.return_value = {
+        "access_token": access_token,
+        "refresh_token": refresh_token,
+        "expires_in": 3600,
+        "scope": "openid email profile",
+    }
+    return resp
+
+
+def _mock_user_info_response(
+    email: str = "user@google.com",
+    name: str = "Test User",
+    google_id: str = "g123",
+    verified: bool = True,
+):
+    resp = MagicMock()
+    resp.status_code = 200
+    resp.json.return_value = {
+        "email": email,
+        "name": name,
+        "id": google_id,
+        "picture": "https://example.com/pic.jpg",
+        "verified_email": verified,
+    }
+    return resp
+
+
+# ── OAuthService.get_google_user_info ────────────────────────────────────────
+
+
+class TestGetGoogleUserInfo:
+    async def test_success(self):
+        svc = OAuthService()
+        token_resp = _mock_token_response()
+        user_info_resp = _mock_user_info_response()
+
+        mock_client = AsyncMock()
+        mock_client.__aenter__ = AsyncMock(return_value=mock_client)
+        mock_client.__aexit__ = AsyncMock(return_value=False)
+        mock_client.post = AsyncMock(return_value=token_resp)
+        mock_client.get = AsyncMock(return_value=user_info_resp)
+
+        with patch(
+            "app.services.auth_service.httpx.AsyncClient", return_value=mock_client
+        ):
+            result = await svc.get_google_user_info(
+                code="authcode", redirect_uri="http://localhost/callback"
+            )
+
+        assert result["email"] == "user@google.com"
+        assert result["google_id"] == "g123"
+        assert result["verified_email"] is True
+        assert result["access_token"] == "access123"
+
+    async def test_token_exchange_fails(self):
+        svc = OAuthService()
+        bad_resp = MagicMock()
+        bad_resp.status_code = 400
+        bad_resp.text = "bad_request"
+
+        mock_client = AsyncMock()
+        mock_client.__aenter__ = AsyncMock(return_value=mock_client)
+        mock_client.__aexit__ = AsyncMock(return_value=False)
+        mock_client.post = AsyncMock(return_value=bad_resp)
+
+        with patch(
+            "app.services.auth_service.httpx.AsyncClient", return_value=mock_client
+        ):
+            with pytest.raises(HTTPException) as exc_info:
+                await svc.get_google_user_info(
+                    code="bad", redirect_uri="http://localhost"
+                )
+        assert exc_info.value.status_code == 400
+
+    async def test_no_access_token_in_response(self):
+        svc = OAuthService()
+        resp = MagicMock()
+        resp.status_code = 200
+        resp.json.return_value = {}  # no access_token
+
+        mock_client = AsyncMock()
+        mock_client.__aenter__ = AsyncMock(return_value=mock_client)
+        mock_client.__aexit__ = AsyncMock(return_value=False)
+        mock_client.post = AsyncMock(return_value=resp)
+
+        with patch(
+            "app.services.auth_service.httpx.AsyncClient", return_value=mock_client
+        ):
+            with pytest.raises(HTTPException) as exc_info:
+                await svc.get_google_user_info(
+                    code="c", redirect_uri="http://localhost"
+                )
+        assert exc_info.value.status_code == 400
+
+    async def test_user_info_fetch_fails(self):
+        svc = OAuthService()
+        token_resp = _mock_token_response()
+        bad_info = MagicMock()
+        bad_info.status_code = 500
+        bad_info.text = "server error"
+
+        mock_client = AsyncMock()
+        mock_client.__aenter__ = AsyncMock(return_value=mock_client)
+        mock_client.__aexit__ = AsyncMock(return_value=False)
+        mock_client.post = AsyncMock(return_value=token_resp)
+        mock_client.get = AsyncMock(return_value=bad_info)
+
+        with patch(
+            "app.services.auth_service.httpx.AsyncClient", return_value=mock_client
+        ):
+            with pytest.raises(HTTPException) as exc_info:
+                await svc.get_google_user_info(
+                    code="c", redirect_uri="http://localhost"
+                )
+        assert exc_info.value.status_code == 400
+
+    async def test_unexpected_exception_becomes_500(self):
+        svc = OAuthService()
+
+        mock_client = AsyncMock()
+        mock_client.__aenter__ = AsyncMock(return_value=mock_client)
+        mock_client.__aexit__ = AsyncMock(return_value=False)
+        mock_client.post = AsyncMock(side_effect=RuntimeError("network down"))
+
+        with patch(
+            "app.services.auth_service.httpx.AsyncClient", return_value=mock_client
+        ):
+            with pytest.raises(HTTPException) as exc_info:
+                await svc.get_google_user_info(
+                    code="c", redirect_uri="http://localhost"
+                )
+        assert exc_info.value.status_code == 500
+
+
+# ── OAuthService.create_tokens_for_user ──────────────────────────────────────
+
+
+class TestCreateTokensForUser:
+    def test_returns_all_fields(self):
+        user = _make_user(id=7)
+        result = OAuthService.create_tokens_for_user(user)
+        assert "access_token" in result
+        assert "refresh_token" in result
+        assert result["token_type"] == "bearer"
+
+    def test_access_token_is_string(self):
+        user = _make_user(id=3)
+        result = OAuthService.create_tokens_for_user(user)
+        assert isinstance(result["access_token"], str)
+        assert len(result["access_token"]) > 0
+
+    def test_refresh_token_is_string(self):
+        user = _make_user(id=5)
+        result = OAuthService.create_tokens_for_user(user)
+        assert isinstance(result["refresh_token"], str)
+        assert len(result["refresh_token"]) > 0
+
+    def test_different_users_get_different_tokens(self):
+        u1 = _make_user(id=1)
+        u2 = _make_user(id=2)
+        tokens1 = OAuthService.create_tokens_for_user(u1)
+        tokens2 = OAuthService.create_tokens_for_user(u2)
+        assert tokens1["access_token"] != tokens2["access_token"]
diff --git a/backend/tests/unit/test_gdpr.py b/backend/tests/unit/test_gdpr.py
new file mode 100644
index 0000000..fd4037c
--- /dev/null
+++ b/backend/tests/unit/test_gdpr.py
@@ -0,0 +1,102 @@
+"""
+Unit tests for GDPR data masking utilities (core/gdpr.py).
+No database or HTTP layer required – pure function tests.
+"""
+
+
+from app.core.gdpr import mask_email, mask_name, mask_from_header
+
+
+class TestMaskEmail:
+    def test_typical_address(self):
+        assert mask_email("john.doe@example.com") == "jo***@e***.com"
+
+    def test_short_local(self):
+        # local part has only 1 char; still returns that char + ***
+        result = mask_email("a@b.de")
+        assert result == "a***@b***.de"
+
+    def test_two_char_local(self):
+        result = mask_email("ab@x.io")
+        assert result == "ab***@x***.io"
+
+    def test_domain_with_subdomain_tld(self):
+        # rsplit('.', 1) splits on the last dot only
+        result = mask_email("user@mail.example.org")
+        assert result == "us***@m***.org"
+
+    def test_empty_string(self):
+        assert mask_email("") == "***"
+
+    def test_no_at_sign(self):
+        assert mask_email("notanemail") == "***"
+
+    def test_preserves_tld(self):
+        result = mask_email("hello@world.co.uk")
+        assert result.endswith(".uk")
+
+    def test_single_char_sld(self):
+        result = mask_email("user@x.com")
+        assert result == "us***@x***.com"
+
+
+class TestMaskName:
+    def test_single_word(self):
+        assert mask_name("Alice") == "Al***"
+
+    def test_two_words(self):
+        assert mask_name("John Doe") == "Jo*** Do***"
+
+    def test_single_char_word(self):
+        result = mask_name("X")
+        assert result == "X***"
+
+    def test_empty_string(self):
+        assert mask_name("") == "***"
+
+    def test_three_words(self):
+        result = mask_name("Jean-Luc Picard")
+        # Two words separated by space
+        parts = result.split(" ")
+        assert len(parts) == 2
+        assert all(p.endswith("***") for p in parts)
+
+    def test_long_name(self):
+        result = mask_name("Alexander")
+        assert result == "Al***"
+
+
+class TestMaskFromHeader:
+    def test_display_name_with_angle_email(self):
+        result = mask_from_header("John Doe <john.doe@example.com>")
+        assert "<" in result
+        assert "jo***" in result
+        assert "Jo***" in result
+
+    def test_plain_email(self):
+        result = mask_from_header("john.doe@example.com")
+        assert result == "jo***@e***.com"
+
+    def test_empty_string(self):
+        assert mask_from_header("") == "***"
+
+    def test_no_display_name_angle_email(self):
+        result = mask_from_header("<user@example.com>")
+        assert result == "us***@e***.com"
+
+    def test_fallback_no_email_pattern(self):
+        # String with no recognisable email → falls back to mask_name
+        result = mask_from_header("JustAName")
+        assert result == "Ju***"
+
+    def test_quoted_display_name(self):
+        result = mask_from_header('"Alice Smith" <alice@example.com>')
+        assert "Al***" in result
+        assert "al***" in result
+
+    def test_angle_email_no_display(self):
+        # Edge: angle brackets but empty display part
+        result = mask_from_header("   <admin@site.org>")
+        # No display name → returns masked email only
+        assert "@" in result
+        assert "***" in result
diff --git a/backend/tests/unit/test_gmail_labels.py b/backend/tests/unit/test_gmail_labels.py
new file mode 100644
index 0000000..08cab79
--- /dev/null
+++ b/backend/tests/unit/test_gmail_labels.py
@@ -0,0 +1,184 @@
+"""
+Unit tests for Gmail label utilities (utils/gmail_labels.py).
+Pure function tests – no database or HTTP layer required.
+"""
+
+
+from app.utils.gmail_labels import (
+    DEFAULT_IMPORT_LABEL_TEMPLATES,
+    MAX_IMPORT_LABELS,
+    _normalize_string_list,
+    normalize_import_label_templates,
+    extract_granted_scopes,
+    extract_import_label_templates,
+    build_gmail_credential_scopes,
+    render_import_labels,
+)
+
+
+class TestNormalizeStringList:
+    def test_basic_dedup(self):
+        result = _normalize_string_list(["a", "A", "b"])
+        assert result == ["a", "b"]
+
+    def test_strips_whitespace(self):
+        result = _normalize_string_list(["  hello  ", "world"])
+        assert result == ["hello", "world"]
+
+    def test_empty_strings_filtered(self):
+        result = _normalize_string_list(["", "  ", "real"])
+        assert result == ["real"]
+
+    def test_none_returns_empty(self):
+        assert _normalize_string_list(None) == []
+
+    def test_preserves_case_in_output(self):
+        # Case-insensitive dedup but preserves original casing
+        result = _normalize_string_list(["Hello", "hello"])
+        assert result == ["Hello"]
+
+    def test_order_preserved(self):
+        items = ["c", "a", "b"]
+        assert _normalize_string_list(items) == ["c", "a", "b"]
+
+
+class TestNormalizeImportLabelTemplates:
+    def test_none_returns_defaults(self):
+        result = normalize_import_label_templates(None)
+        assert result == DEFAULT_IMPORT_LABEL_TEMPLATES
+
+    def test_empty_list_returns_defaults(self):
+        result = normalize_import_label_templates([])
+        assert result == DEFAULT_IMPORT_LABEL_TEMPLATES
+
+    def test_custom_templates(self):
+        result = normalize_import_label_templates(["archive", "inbox"])
+        assert result == ["archive", "inbox"]
+
+    def test_deduplicates(self):
+        result = normalize_import_label_templates(["tag", "TAG"])
+        assert result == ["tag"]
+
+    def test_returns_copy_of_defaults(self):
+        result = normalize_import_label_templates(None)
+        result.append("extra")
+        assert "extra" not in DEFAULT_IMPORT_LABEL_TEMPLATES
+
+
+class TestExtractGrantedScopes:
+    def test_list_format(self):
+        result = extract_granted_scopes(["scope1", "scope2"])
+        assert result == ["scope1", "scope2"]
+
+    def test_list_filters_non_strings(self):
+        result = extract_granted_scopes(["valid", 42, None, "other"])
+        assert result == ["valid", "other"]
+
+    def test_dict_format(self):
+        data = {"granted_scopes": ["https://mail.google.com/", "openid"]}
+        result = extract_granted_scopes(data)
+        assert "https://mail.google.com/" in result
+
+    def test_dict_missing_granted_scopes(self):
+        result = extract_granted_scopes({})
+        assert result == []
+
+    def test_dict_non_list_granted_scopes(self):
+        result = extract_granted_scopes({"granted_scopes": "not-a-list"})
+        assert result == []
+
+    def test_unrecognized_type(self):
+        assert extract_granted_scopes(None) == []
+        assert extract_granted_scopes(42) == []
+        assert extract_granted_scopes("string") == []
+
+
+class TestExtractImportLabelTemplates:
+    def test_dict_with_templates(self):
+        data = {"import_label_templates": ["archive", "imported"]}
+        result = extract_import_label_templates(data)
+        assert result == ["archive", "imported"]
+
+    def test_dict_missing_key(self):
+        result = extract_import_label_templates({})
+        assert result == DEFAULT_IMPORT_LABEL_TEMPLATES
+
+    def test_non_dict(self):
+        assert extract_import_label_templates(None) == DEFAULT_IMPORT_LABEL_TEMPLATES
+        assert extract_import_label_templates([]) == DEFAULT_IMPORT_LABEL_TEMPLATES
+
+    def test_empty_templates_falls_back_to_defaults(self):
+        result = extract_import_label_templates({"import_label_templates": []})
+        assert result == DEFAULT_IMPORT_LABEL_TEMPLATES
+
+    def test_filters_non_strings(self):
+        data = {"import_label_templates": ["valid", 123, None]}
+        result = extract_import_label_templates(data)
+        assert result == ["valid"]
+
+
+class TestBuildGmailCredentialScopes:
+    def test_basic(self):
+        result = build_gmail_credential_scopes(
+            ["https://mail.google.com/"], ["{{source_email}}", "imported"]
+        )
+        assert "granted_scopes" in result
+        assert "import_label_templates" in result
+        assert "https://mail.google.com/" in result["granted_scopes"]
+
+    def test_none_granted_scopes(self):
+        result = build_gmail_credential_scopes(None)
+        assert result["granted_scopes"] == []
+        assert result["import_label_templates"] == DEFAULT_IMPORT_LABEL_TEMPLATES
+
+    def test_deduplication(self):
+        result = build_gmail_credential_scopes(["scope", "SCOPE"])
+        assert result["granted_scopes"] == ["scope"]
+
+
+class TestRenderImportLabels:
+    def test_source_email_substitution(self):
+        result = render_import_labels(["{{source_email}}"], "user@example.com")
+        assert result == ["user@example.com"]
+
+    def test_literal_template(self):
+        result = render_import_labels(["imported"], "user@example.com")
+        assert result == ["imported"]
+
+    def test_mixed_templates(self):
+        result = render_import_labels(
+            ["{{source_email}}", "imported"], "user@example.com"
+        )
+        assert result == ["user@example.com", "imported"]
+
+    def test_deduplication(self):
+        result = render_import_labels(["tag", "TAG"], "user@example.com")
+        assert result == ["tag"]
+
+    def test_none_source_email(self):
+        # Template containing source_email placeholder with no email → empty string,
+        # gets stripped, filtered out.
+        result = render_import_labels(["{{source_email}}"], None)
+        assert result == []
+
+    def test_empty_source_email(self):
+        result = render_import_labels(["{{source_email}}"], "")
+        assert result == []
+
+    def test_none_templates_uses_defaults(self):
+        result = render_import_labels(None, "user@example.com")
+        assert "user@example.com" in result
+        assert "imported" in result
+
+    def test_whitespace_only_template_filtered(self):
+        # Whitespace-only entries are stripped to empty strings and then filtered
+        # by normalize_import_label_templates. When no valid templates remain,
+        # defaults are returned. The source_email template then renders to the
+        # source email, and "imported" is included too.
+        result = render_import_labels(["   "], "user@example.com")
+        # normalize_import_label_templates falls back to defaults → includes
+        # {{source_email}} (renders to "user@example.com") and "imported"
+        assert result == ["user@example.com", "imported"]
+
+    def test_max_labels_constant(self):
+        assert MAX_IMPORT_LABELS == 10
diff --git a/backend/tests/unit/test_logs_endpoints.py b/backend/tests/unit/test_logs_endpoints.py
new file mode 100644
index 0000000..c68a186
--- /dev/null
+++ b/backend/tests/unit/test_logs_endpoints.py
@@ -0,0 +1,335 @@
+"""
+Unit tests for processing logs / runs endpoints (api/v1/endpoints/logs.py).
+
+All database interactions and auth dependencies are mocked.
+"""
+
+import pytest
+from datetime import datetime, timezone
+from unittest.mock import AsyncMock, MagicMock
+
+from httpx import AsyncClient, ASGITransport
+
+from app.main import create_application
+from app.core.database import get_db
+from app.core.deps import get_current_active_user
+from app.models.database_models import (
+    User,
+    ProcessingRun,
+    ProcessingLog,
+    SubscriptionTier,
+)
+
+# ── helpers ──────────────────────────────────────────────────────────────────
+
+
+def _make_user(**overrides) -> MagicMock:
+    defaults = dict(
+        id=1,
+        email="user@example.com",
+        full_name="Test User",
+        is_active=True,
+        is_superuser=False,
+        subscription_tier=SubscriptionTier.FREE,
+        subscription_status="active",
+        google_id=None,
+        oauth_provider=None,
+        last_login_at=None,
+        created_at=datetime.now(timezone.utc),
+        updated_at=datetime.now(timezone.utc),
+        stripe_customer_id=None,
+        stripe_subscription_id=None,
+        subscription_expires_at=None,
+    )
+    defaults.update(overrides)
+    u = MagicMock(spec=User)
+    for k, v in defaults.items():
+        setattr(u, k, v)
+    return u
+
+
+def _make_run(**overrides) -> MagicMock:
+    defaults = dict(
+        id=1,
+        mail_account_id=10,
+        started_at=datetime.now(timezone.utc),
+        completed_at=datetime.now(timezone.utc),
+        duration_seconds=1.5,
+        emails_fetched=3,
+        emails_forwarded=3,
+        emails_failed=0,
+        status="completed",
+        error_message=None,
+    )
+    defaults.update(overrides)
+    run = MagicMock(spec=ProcessingRun)
+    for k, v in defaults.items():
+        setattr(run, k, v)
+    return run
+
+
+def _make_log(**overrides) -> MagicMock:
+    defaults = dict(
+        id=1,
+        timestamp=datetime.now(timezone.utc),
+        level="INFO",
+        message="processed",
+        email_subject="Hello",
+        email_from="sender@example.com",
+        success=True,
+        mail_account_id=10,
+        processing_run_id=1,
+        email_size_bytes=1024,
+        error_details=None,
+    )
+    defaults.update(overrides)
+    log = MagicMock(spec=ProcessingLog)
+    for k, v in defaults.items():
+        setattr(log, k, v)
+    return log
+
+
+def _scalar_one(value):
+    r = MagicMock()
+    r.scalar_one.return_value = value
+    return r
+
+
+def _scalar_one_or_none(value):
+    r = MagicMock()
+    r.scalar_one_or_none.return_value = value
+    return r
+
+
+def _rows_all(rows):
+    r = MagicMock()
+    r.all.return_value = rows
+    return r
+
+
+def _scalars_all(values):
+    r = MagicMock()
+    scalars = MagicMock()
+    scalars.all.return_value = values
+    r.scalars.return_value = scalars
+    return r
+
+
+@pytest.fixture
+def app():
+    return create_application()
+
+
+@pytest.fixture
+def mock_db():
+    db = AsyncMock()
+    return db
+
+
+@pytest.fixture
+def current_user():
+    return _make_user()
+
+
+@pytest.fixture
+async def auth_client(app, current_user, mock_db):
+    async def _override_user():
+        return current_user
+
+    async def _override_db():
+        yield mock_db
+
+    app.dependency_overrides[get_current_active_user] = _override_user
+    app.dependency_overrides[get_db] = _override_db
+
+    transport = ASGITransport(app=app)
+    async with AsyncClient(transport=transport, base_url="http://test") as client:
+        yield client
+
+    app.dependency_overrides.clear()
+
+
+# ── GET /logs ─────────────────────────────────────────────────────────────────
+
+
+class TestListProcessingRuns:
+    async def test_returns_paginated_list(self, auth_client, mock_db):
+        run = _make_run()
+        # The endpoint queries total count then rows
+        # First execute → count, second execute → rows with joined columns
+        row = MagicMock()
+        row.ProcessingRun = run
+        row.name = "My Account"
+        row.email_address = "me@example.com"
+
+        mock_db.execute = AsyncMock(
+            side_effect=[
+                _scalar_one(1),  # count query
+                _rows_all([row]),  # data query
+            ]
+        )
+        response = await auth_client.get("/api/v1/processing-runs")
+        assert response.status_code == 200
+        data = response.json()
+        assert "items" in data
+        assert "total" in data
+        assert data["total"] == 1
+        assert len(data["items"]) == 1
+
+    async def test_empty_result(self, auth_client, mock_db):
+        mock_db.execute = AsyncMock(
+            side_effect=[
+                _scalar_one(0),
+                _rows_all([]),
+            ]
+        )
+        response = await auth_client.get("/api/v1/processing-runs")
+        assert response.status_code == 200
+        data = response.json()
+        assert data["items"] == []
+        assert data["total"] == 0
+
+    async def test_unauthenticated_401(self, app):
+        transport = ASGITransport(app=app)
+        async with AsyncClient(transport=transport, base_url="http://test") as client:
+            response = await client.get("/api/v1/processing-runs")
+        assert response.status_code == 401
+
+    async def test_pagination_params(self, auth_client, mock_db):
+        mock_db.execute = AsyncMock(
+            side_effect=[
+                _scalar_one(0),
+                _rows_all([]),
+            ]
+        )
+        response = await auth_client.get("/api/v1/processing-runs?page=2&page_size=5")
+        assert response.status_code == 200
+        data = response.json()
+        assert data["page"] == 2
+        assert data["page_size"] == 5
+
+    async def test_filter_by_account_id(self, auth_client, mock_db):
+        mock_db.execute = AsyncMock(
+            side_effect=[
+                _scalar_one(0),
+                _rows_all([]),
+            ]
+        )
+        response = await auth_client.get("/api/v1/processing-runs?account_id=5")
+        assert response.status_code == 200
+
+    async def test_filter_by_status(self, auth_client, mock_db):
+        mock_db.execute = AsyncMock(
+            side_effect=[
+                _scalar_one(0),
+                _rows_all([]),
+            ]
+        )
+        response = await auth_client.get("/api/v1/processing-runs?status=completed")
+        assert response.status_code == 200
+
+    async def test_filter_has_emails(self, auth_client, mock_db):
+        mock_db.execute = AsyncMock(
+            side_effect=[
+                _scalar_one(0),
+                _rows_all([]),
+            ]
+        )
+        response = await auth_client.get("/api/v1/processing-runs?has_emails=true")
+        assert response.status_code == 200
+
+
+# ── GET /logs/{run_id} ────────────────────────────────────────────────────────
+
+
+class TestGetProcessingRun:
+    async def test_returns_run(self, auth_client, mock_db):
+        run = _make_run(id=42)
+        row = MagicMock()
+        row.ProcessingRun = run
+        row.name = "Account"
+        row.email_address = "me@example.com"
+
+        result = MagicMock()
+        result.one_or_none.return_value = row
+        mock_db.execute = AsyncMock(return_value=result)
+
+        response = await auth_client.get("/api/v1/processing-runs/42")
+        assert response.status_code == 200
+        data = response.json()
+        assert data["id"] == 42
+
+    async def test_404_when_not_found(self, auth_client, mock_db):
+        result = MagicMock()
+        result.one_or_none.return_value = None
+        mock_db.execute = AsyncMock(return_value=result)
+
+        response = await auth_client.get("/api/v1/processing-runs/999")
+        assert response.status_code == 404
+
+
+# ── GET /logs/{run_id}/logs ───────────────────────────────────────────────────
+
+
+class TestGetRunLogs:
+    async def test_returns_log_entries(self, auth_client, mock_db):
+        run = _make_run(id=1)
+        log_entry = _make_log(processing_run_id=1)
+
+        mock_db.execute = AsyncMock(
+            side_effect=[
+                _scalar_one_or_none(run),  # ownership check
+                _scalar_one(1),  # count
+                _scalars_all([log_entry]),  # log entries
+            ]
+        )
+        response = await auth_client.get("/api/v1/processing-runs/1/logs")
+        assert response.status_code == 200
+        data = response.json()
+        assert "items" in data
+        assert len(data["items"]) == 1
+
+    async def test_404_when_run_not_found(self, auth_client, mock_db):
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(None))
+        response = await auth_client.get("/api/v1/processing-runs/999/logs")
+        assert response.status_code == 404
+
+    async def test_empty_log_entries(self, auth_client, mock_db):
+        run = _make_run(id=1)
+        mock_db.execute = AsyncMock(
+            side_effect=[
+                _scalar_one_or_none(run),
+                _scalar_one(0),
+                _scalars_all([]),
+            ]
+        )
+        response = await auth_client.get("/api/v1/processing-runs/1/logs")
+        assert response.status_code == 200
+        data = response.json()
+        assert data["items"] == []
+        assert data["total"] == 0
+
+
+# ── helper: _paginate ─────────────────────────────────────────────────────────
+
+
+class TestPaginateHelper:
+    def test_single_page(self):
+        from app.api.v1.endpoints.logs import _paginate
+
+        result = _paginate(total=10, page=1, page_size=20)
+        assert result["total"] == 10
+        assert result["pages"] == 1
+
+    def test_multiple_pages(self):
+        from app.api.v1.endpoints.logs import _paginate
+
+        result = _paginate(total=25, page=2, page_size=10)
+        assert result["pages"] == 3
+
+    def test_zero_total(self):
+        from app.api.v1.endpoints.logs import _paginate
+
+        result = _paginate(total=0, page=1, page_size=20)
+        assert result["pages"] == 1
+        assert result["total"] == 0
diff --git a/backend/tests/unit/test_notification_service.py b/backend/tests/unit/test_notification_service.py
new file mode 100644
index 0000000..6d1d72c
--- /dev/null
+++ b/backend/tests/unit/test_notification_service.py
@@ -0,0 +1,215 @@
+"""
+Unit tests for the notification service (services/notification_service.py).
+
+All external dependencies (database, Apprise) are mocked so no real
+infrastructure is needed.
+"""
+
+from unittest.mock import AsyncMock, MagicMock, patch
+
+from app.services.notification_service import (
+    send_user_notification,
+    send_admin_notification,
+    test_notification as _test_notification,
+    _send_apprise,
+)
+
+# ── helpers ──────────────────────────────────────────────────────────────────
+
+
+def _make_notification_config(
+    *,
+    id: int = 1,
+    user_id: int = 42,
+    apprise_url: str = "json://localhost",
+    is_enabled: bool = True,
+    notify_on_errors: bool = True,
+    notify_on_success: bool = False,
+):
+    cfg = MagicMock()
+    cfg.id = id
+    cfg.user_id = user_id
+    cfg.apprise_url = apprise_url
+    cfg.is_enabled = is_enabled
+    cfg.notify_on_errors = notify_on_errors
+    cfg.notify_on_success = notify_on_success
+    return cfg
+
+
+def _make_db(configs=None):
+    """Return an AsyncMock db with execute returning the given config list."""
+    db = AsyncMock()
+    result = MagicMock()
+    scalars = MagicMock()
+    scalars.all.return_value = configs or []
+    result.scalars.return_value = scalars
+    db.execute = AsyncMock(return_value=result)
+    return db
+
+
+# ── send_user_notification ────────────────────────────────────────────────────
+
+
+class TestSendUserNotification:
+    async def test_returns_zero_when_no_configs(self):
+        db = _make_db(configs=[])
+        count = await send_user_notification(db, user_id=1, title="T", body="B")
+        assert count == 0
+
+    async def test_sends_to_error_channel(self):
+        cfg = _make_notification_config(notify_on_errors=True, notify_on_success=False)
+        db = _make_db(configs=[cfg])
+        with patch(
+            "app.services.notification_service._send_apprise",
+            new=AsyncMock(return_value=True),
+        ) as mock_send:
+            count = await send_user_notification(
+                db, user_id=42, title="Err", body="msg", notify_on_error=True
+            )
+        assert count == 1
+        mock_send.assert_awaited_once()
+
+    async def test_skips_error_channel_for_success_notification(self):
+        cfg = _make_notification_config(notify_on_errors=True, notify_on_success=False)
+        db = _make_db(configs=[cfg])
+        with patch(
+            "app.services.notification_service._send_apprise",
+            new=AsyncMock(return_value=True),
+        ) as mock_send:
+            count = await send_user_notification(
+                db, user_id=42, title="Ok", body="msg", notify_on_error=False
+            )
+        assert count == 0
+        mock_send.assert_not_awaited()
+
+    async def test_sends_to_success_channel(self):
+        cfg = _make_notification_config(notify_on_errors=False, notify_on_success=True)
+        db = _make_db(configs=[cfg])
+        with patch(
+            "app.services.notification_service._send_apprise",
+            new=AsyncMock(return_value=True),
+        ) as mock_send:
+            count = await send_user_notification(
+                db, user_id=42, title="Ok", body="msg", notify_on_error=False
+            )
+        assert count == 1
+        mock_send.assert_awaited_once()
+
+    async def test_failed_apprise_not_counted(self):
+        cfg = _make_notification_config(notify_on_errors=True)
+        db = _make_db(configs=[cfg])
+        with patch(
+            "app.services.notification_service._send_apprise",
+            new=AsyncMock(return_value=False),
+        ):
+            count = await send_user_notification(db, user_id=42, title="T", body="B")
+        assert count == 0
+
+    async def test_exception_in_apprise_swallowed(self):
+        cfg = _make_notification_config(notify_on_errors=True)
+        db = _make_db(configs=[cfg])
+        with patch(
+            "app.services.notification_service._send_apprise",
+            new=AsyncMock(side_effect=Exception("boom")),
+        ):
+            count = await send_user_notification(db, user_id=42, title="T", body="B")
+        assert count == 0
+
+    async def test_multiple_channels_counted_individually(self):
+        cfg1 = _make_notification_config(id=1, notify_on_errors=True)
+        cfg2 = _make_notification_config(id=2, notify_on_errors=True)
+        db = _make_db(configs=[cfg1, cfg2])
+        with patch(
+            "app.services.notification_service._send_apprise",
+            new=AsyncMock(return_value=True),
+        ):
+            count = await send_user_notification(db, user_id=42, title="T", body="B")
+        assert count == 2
+
+
+# ── send_admin_notification ───────────────────────────────────────────────────
+
+
+class TestSendAdminNotification:
+    async def test_returns_zero_when_no_configs(self):
+        db = _make_db(configs=[])
+        count = await send_admin_notification(db, title="T", body="B")
+        assert count == 0
+
+    async def test_sends_to_enabled_channel(self):
+        cfg = MagicMock()
+        cfg.id = 1
+        cfg.apprise_url = "json://localhost"
+        db = _make_db(configs=[cfg])
+        with patch(
+            "app.services.notification_service._send_apprise",
+            new=AsyncMock(return_value=True),
+        ):
+            count = await send_admin_notification(db, title="T", body="B")
+        assert count == 1
+
+    async def test_exception_in_channel_swallowed(self):
+        cfg = MagicMock()
+        cfg.id = 1
+        cfg.apprise_url = "json://localhost"
+        db = _make_db(configs=[cfg])
+        with patch(
+            "app.services.notification_service._send_apprise",
+            new=AsyncMock(side_effect=RuntimeError("oops")),
+        ):
+            count = await send_admin_notification(db, title="T", body="B")
+        assert count == 0
+
+
+# ── test_notification ─────────────────────────────────────────────────────────
+
+
+class TestTestNotification:
+    async def test_success(self):
+        with patch(
+            "app.services.notification_service._send_apprise",
+            new=AsyncMock(return_value=True),
+        ):
+            ok, msg = await _test_notification("json://localhost")
+        assert ok is True
+        assert "success" in msg.lower()
+
+    async def test_failure_from_apprise(self):
+        with patch(
+            "app.services.notification_service._send_apprise",
+            new=AsyncMock(return_value=False),
+        ):
+            ok, msg = await _test_notification("json://localhost")
+        assert ok is False
+
+    async def test_exception_returns_false(self):
+        with patch(
+            "app.services.notification_service._send_apprise",
+            new=AsyncMock(side_effect=Exception("network error")),
+        ):
+            ok, msg = await _test_notification("json://localhost")
+        assert ok is False
+        assert "error" in msg.lower()
+
+
+# ── _send_apprise internal helper ─────────────────────────────────────────────
+
+
+class TestSendApprise:
+    async def test_invalid_url_returns_false(self):
+        # Apprise.add() returns False for unrecognised schemes
+        with patch("app.services.notification_service.apprise") as mock_apprise_module:
+            ap_instance = MagicMock()
+            ap_instance.add.return_value = False
+            mock_apprise_module.Apprise.return_value = ap_instance
+            result = await _send_apprise("not-a-valid-url://", "T", "B")
+        assert result is False
+
+    async def test_valid_url_returns_true(self):
+        with patch("app.services.notification_service.apprise") as mock_apprise_module:
+            ap_instance = MagicMock()
+            ap_instance.add.return_value = True
+            ap_instance.async_notify = AsyncMock(return_value=True)
+            mock_apprise_module.Apprise.return_value = ap_instance
+            result = await _send_apprise("json://localhost", "T", "B")
+        assert result is True
diff --git a/backend/tests/unit/test_notifications_endpoints.py b/backend/tests/unit/test_notifications_endpoints.py
new file mode 100644
index 0000000..5075a1d
--- /dev/null
+++ b/backend/tests/unit/test_notifications_endpoints.py
@@ -0,0 +1,278 @@
+"""
+Unit tests for notification config endpoints (api/v1/endpoints/notifications.py).
+
+All database interactions and auth dependencies are mocked.
+"""
+
+import pytest
+from datetime import datetime, timezone
+from unittest.mock import AsyncMock, MagicMock, patch
+
+from httpx import AsyncClient, ASGITransport
+
+from app.main import create_application
+from app.core.database import get_db
+from app.core.deps import get_current_active_user
+from app.models.database_models import (
+    User,
+    NotificationConfig,
+    NotificationChannel,
+    SubscriptionTier,
+)
+
+# ── helpers ──────────────────────────────────────────────────────────────────
+
+
+def _make_user(**overrides) -> MagicMock:
+    defaults = dict(
+        id=1,
+        email="user@example.com",
+        full_name="Test User",
+        is_active=True,
+        is_superuser=False,
+        subscription_tier=SubscriptionTier.FREE,
+        subscription_status="active",
+        google_id=None,
+        oauth_provider=None,
+        last_login_at=None,
+        created_at=datetime.now(timezone.utc),
+        updated_at=datetime.now(timezone.utc),
+        stripe_customer_id=None,
+        stripe_subscription_id=None,
+        subscription_expires_at=None,
+    )
+    defaults.update(overrides)
+    u = MagicMock(spec=User)
+    for k, v in defaults.items():
+        setattr(u, k, v)
+    return u
+
+
+def _make_notification_config(**overrides) -> MagicMock:
+    defaults = dict(
+        id=1,
+        user_id=1,
+        name="Test Notification",
+        apprise_url="json://localhost",
+        channel=NotificationChannel.WEBHOOK,
+        is_enabled=True,
+        config={},
+        notify_on_errors=True,
+        notify_on_success=False,
+        notify_threshold=3,
+        created_at=datetime.now(timezone.utc),
+        updated_at=datetime.now(timezone.utc),
+    )
+    defaults.update(overrides)
+    cfg = MagicMock(spec=NotificationConfig)
+    for k, v in defaults.items():
+        setattr(cfg, k, v)
+    return cfg
+
+
+def _scalar_one_or_none(value):
+    r = MagicMock()
+    r.scalar_one_or_none.return_value = value
+    return r
+
+
+def _scalars_all(values):
+    r = MagicMock()
+    scalars = MagicMock()
+    scalars.all.return_value = values
+    r.scalars.return_value = scalars
+    return r
+
+
+@pytest.fixture
+def app():
+    return create_application()
+
+
+@pytest.fixture
+def mock_db():
+    db = AsyncMock()
+    db.commit = AsyncMock()
+    db.refresh = AsyncMock()
+    db.add = MagicMock()
+    db.delete = AsyncMock()
+    return db
+
+
+@pytest.fixture
+def current_user():
+    return _make_user()
+
+
+@pytest.fixture
+async def auth_client(app, current_user, mock_db):
+    async def _override_user():
+        return current_user
+
+    async def _override_db():
+        yield mock_db
+
+    app.dependency_overrides[get_current_active_user] = _override_user
+    app.dependency_overrides[get_db] = _override_db
+
+    transport = ASGITransport(app=app)
+    async with AsyncClient(transport=transport, base_url="http://test") as client:
+        yield client
+
+    app.dependency_overrides.clear()
+
+
+# ── POST /notifications ───────────────────────────────────────────────────────
+
+
+class TestCreateNotificationConfig:
+    async def test_creates_config_201(self, auth_client, mock_db, current_user):
+        created_cfg = _make_notification_config()
+
+        # db.refresh must populate the object returned from the endpoint
+        async def _refresh(obj):
+            for k, v in vars(created_cfg).items():
+                if not k.startswith("_"):
+                    try:
+                        setattr(obj, k, v)
+                    except AttributeError:
+                        pass
+
+        mock_db.refresh = AsyncMock(side_effect=_refresh)
+
+        response = await auth_client.post(
+            "/api/v1/notifications",
+            json={
+                "name": "My Webhook",
+                "apprise_url": "json://localhost",
+                "channel": "webhook",
+                "is_enabled": True,
+                "config": {},
+                "notify_on_errors": True,
+                "notify_on_success": False,
+                "notify_threshold": 3,
+            },
+        )
+        assert response.status_code == 201
+
+    async def test_unauthenticated_401(self, app):
+        transport = ASGITransport(app=app)
+        async with AsyncClient(transport=transport, base_url="http://test") as client:
+            response = await client.post(
+                "/api/v1/notifications",
+                json={
+                    "name": "x",
+                    "apprise_url": "json://localhost",
+                    "channel": "webhook",
+                    "config": {},
+                },
+            )
+        assert response.status_code == 401
+
+
+# ── GET /notifications ────────────────────────────────────────────────────────
+
+
+class TestListNotificationConfigs:
+    async def test_returns_list(self, auth_client, mock_db):
+        cfg1 = _make_notification_config(id=1)
+        cfg2 = _make_notification_config(id=2)
+        mock_db.execute = AsyncMock(return_value=_scalars_all([cfg1, cfg2]))
+        response = await auth_client.get("/api/v1/notifications")
+        assert response.status_code == 200
+        assert isinstance(response.json(), list)
+        assert len(response.json()) == 2
+
+    async def test_returns_empty_list(self, auth_client, mock_db):
+        mock_db.execute = AsyncMock(return_value=_scalars_all([]))
+        response = await auth_client.get("/api/v1/notifications")
+        assert response.status_code == 200
+        assert response.json() == []
+
+
+# ── GET /notifications/{id} ───────────────────────────────────────────────────
+
+
+class TestGetNotificationConfig:
+    async def test_returns_config(self, auth_client, mock_db):
+        cfg = _make_notification_config(id=5)
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(cfg))
+        response = await auth_client.get("/api/v1/notifications/5")
+        assert response.status_code == 200
+
+    async def test_404_when_not_found(self, auth_client, mock_db):
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(None))
+        response = await auth_client.get("/api/v1/notifications/999")
+        assert response.status_code == 404
+
+
+# ── PUT /notifications/{id} ───────────────────────────────────────────────────
+
+
+class TestUpdateNotificationConfig:
+    async def test_updates_config(self, auth_client, mock_db):
+        cfg = _make_notification_config(id=5)
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(cfg))
+        mock_db.refresh = AsyncMock(side_effect=lambda obj: None)
+
+        response = await auth_client.put(
+            "/api/v1/notifications/5",
+            json={"name": "Updated Name"},
+        )
+        assert response.status_code == 200
+
+    async def test_404_when_not_found(self, auth_client, mock_db):
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(None))
+        response = await auth_client.put(
+            "/api/v1/notifications/999",
+            json={"name": "Updated"},
+        )
+        assert response.status_code == 404
+
+
+# ── DELETE /notifications/{id} ────────────────────────────────────────────────
+
+
+class TestDeleteNotificationConfig:
+    async def test_deletes_config_204(self, auth_client, mock_db):
+        cfg = _make_notification_config(id=5)
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(cfg))
+        response = await auth_client.delete("/api/v1/notifications/5")
+        assert response.status_code == 204
+        mock_db.delete.assert_awaited_once_with(cfg)
+
+    async def test_404_when_not_found(self, auth_client, mock_db):
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(None))
+        response = await auth_client.delete("/api/v1/notifications/999")
+        assert response.status_code == 404
+
+
+# ── POST /notifications/test ──────────────────────────────────────────────────
+
+
+class TestTestNotificationConfig:
+    async def test_test_success(self, auth_client):
+        with patch(
+            "app.api.v1.endpoints.notifications.test_notification",
+            new=AsyncMock(return_value=(True, "sent successfully")),
+        ):
+            response = await auth_client.post(
+                "/api/v1/notifications/test",
+                json={"apprise_url": "json://localhost"},
+            )
+        assert response.status_code == 200
+        data = response.json()
+        assert data["success"] is True
+
+    async def test_test_failure(self, auth_client):
+        with patch(
+            "app.api.v1.endpoints.notifications.test_notification",
+            new=AsyncMock(return_value=(False, "delivery failed")),
+        ):
+            response = await auth_client.post(
+                "/api/v1/notifications/test",
+                json={"apprise_url": "invalid://url"},
+            )
+        assert response.status_code == 200
+        data = response.json()
+        assert data["success"] is False
diff --git a/backend/tests/unit/test_users_endpoints.py b/backend/tests/unit/test_users_endpoints.py
new file mode 100644
index 0000000..edf2dde
--- /dev/null
+++ b/backend/tests/unit/test_users_endpoints.py
@@ -0,0 +1,247 @@
+"""
+Unit tests for user profile and SMTP config endpoints (api/v1/endpoints/users.py).
+
+All database interactions and auth dependencies are mocked.
+"""
+
+import pytest
+from datetime import datetime, timezone
+from unittest.mock import AsyncMock, MagicMock
+
+from httpx import AsyncClient, ASGITransport
+
+from app.main import create_application
+from app.core.database import get_db
+from app.core.deps import get_current_active_user
+from app.models.database_models import User, UserSmtpConfig, SubscriptionTier
+
+# ── helpers ──────────────────────────────────────────────────────────────────
+
+
+def _make_user(**overrides) -> MagicMock:
+    defaults = dict(
+        id=1,
+        email="user@example.com",
+        full_name="Test User",
+        is_active=True,
+        is_superuser=False,
+        subscription_tier=SubscriptionTier.FREE,
+        subscription_status="active",
+        google_id=None,
+        oauth_provider=None,
+        last_login_at=None,
+        created_at=datetime.now(timezone.utc),
+        updated_at=datetime.now(timezone.utc),
+        stripe_customer_id=None,
+        stripe_subscription_id=None,
+        subscription_expires_at=None,
+    )
+    defaults.update(overrides)
+    u = MagicMock(spec=User)
+    for k, v in defaults.items():
+        setattr(u, k, v)
+    return u
+
+
+def _make_smtp_config(**overrides) -> MagicMock:
+    defaults = dict(
+        id=1,
+        user_id=1,
+        host="smtp.example.com",
+        port=587,
+        username="user@example.com",
+        encrypted_password="encrypted",
+        use_tls=True,
+        created_at=datetime.now(timezone.utc),
+        updated_at=datetime.now(timezone.utc),
+    )
+    defaults.update(overrides)
+    cfg = MagicMock(spec=UserSmtpConfig)
+    for k, v in defaults.items():
+        setattr(cfg, k, v)
+    return cfg
+
+
+def _scalar_one_or_none(value):
+    r = MagicMock()
+    r.scalar_one_or_none.return_value = value
+    return r
+
+
+@pytest.fixture
+def app():
+    return create_application()
+
+
+@pytest.fixture
+def mock_db():
+    db = AsyncMock()
+    db.commit = AsyncMock()
+    db.refresh = AsyncMock()
+    db.add = MagicMock()
+    db.delete = AsyncMock()
+    return db
+
+
+@pytest.fixture
+def current_user():
+    return _make_user()
+
+
+@pytest.fixture
+async def auth_client(app, current_user, mock_db):
+    async def _override_user():
+        return current_user
+
+    async def _override_db():
+        yield mock_db
+
+    app.dependency_overrides[get_current_active_user] = _override_user
+    app.dependency_overrides[get_db] = _override_db
+
+    transport = ASGITransport(app=app)
+    async with AsyncClient(transport=transport, base_url="http://test") as client:
+        yield client
+
+    app.dependency_overrides.clear()
+
+
+# ── GET /me ───────────────────────────────────────────────────────────────────
+
+
+class TestGetMe:
+    async def test_returns_user_data(self, auth_client, current_user):
+        response = await auth_client.get("/api/v1/users/me")
+        assert response.status_code == 200
+        data = response.json()
+        assert data["email"] == current_user.email
+
+    async def test_unauthenticated_401(self, app):
+        transport = ASGITransport(app=app)
+        async with AsyncClient(transport=transport, base_url="http://test") as client:
+            response = await client.get("/api/v1/users/me")
+        assert response.status_code == 401
+
+
+# ── PUT /me ───────────────────────────────────────────────────────────────────
+
+
+class TestUpdateMe:
+    async def test_update_full_name(self, auth_client, mock_db, current_user):
+        mock_db.refresh = AsyncMock(
+            side_effect=lambda obj: setattr(obj, "full_name", "Updated Name")
+        )
+        response = await auth_client.put(
+            "/api/v1/users/me", json={"full_name": "Updated Name"}
+        )
+        assert response.status_code == 200
+
+    async def test_update_email(self, auth_client, mock_db, current_user):
+        mock_db.refresh = AsyncMock(
+            side_effect=lambda obj: setattr(obj, "email", "new@example.com")
+        )
+        response = await auth_client.put(
+            "/api/v1/users/me", json={"email": "new@example.com"}
+        )
+        assert response.status_code == 200
+
+
+# ── GET /smtp-config ──────────────────────────────────────────────────────────
+
+
+class TestGetSmtpConfig:
+    async def test_returns_config_when_exists(self, auth_client, mock_db):
+        cfg = _make_smtp_config()
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(cfg))
+        response = await auth_client.get("/api/v1/users/smtp-config")
+        assert response.status_code == 200
+        data = response.json()
+        assert data["host"] == "smtp.example.com"
+        assert data["port"] == 587
+        assert "has_password" in data
+        # Password must not be exposed
+        assert "encrypted_password" not in data
+
+    async def test_returns_404_when_no_config(self, auth_client, mock_db):
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(None))
+        response = await auth_client.get("/api/v1/users/smtp-config")
+        assert response.status_code == 404
+
+
+# ── PUT /smtp-config ──────────────────────────────────────────────────────────
+
+
+class TestUpsertSmtpConfig:
+    async def test_creates_new_config(self, auth_client, mock_db):
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(None))
+
+        # db.refresh populates the new config object with required fields
+        async def _refresh(obj):
+            obj.id = 1
+            obj.user_id = 1
+            obj.host = "smtp.example.com"
+            obj.port = 587
+            obj.username = "user@example.com"
+            obj.encrypted_password = "encrypted"
+            obj.use_tls = True
+            obj.created_at = datetime.now(timezone.utc)
+            obj.updated_at = datetime.now(timezone.utc)
+
+        mock_db.refresh = AsyncMock(side_effect=_refresh)
+
+        from unittest.mock import patch
+
+        with patch(
+            "app.api.v1.endpoints.users.encrypt_credential", return_value="encrypted"
+        ):
+            response = await auth_client.put(
+                "/api/v1/users/smtp-config",
+                json={
+                    "host": "smtp.example.com",
+                    "port": 587,
+                    "username": "user@example.com",
+                    "password": "secret",
+                    "use_tls": True,
+                },
+            )
+        assert response.status_code == 200
+
+    async def test_updates_existing_config(self, auth_client, mock_db):
+        existing = _make_smtp_config()
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(existing))
+        mock_db.refresh = AsyncMock(side_effect=lambda obj: None)
+
+        from unittest.mock import patch
+
+        with patch(
+            "app.api.v1.endpoints.users.encrypt_credential", return_value="encrypted"
+        ):
+            response = await auth_client.put(
+                "/api/v1/users/smtp-config",
+                json={
+                    "host": "newsmtp.example.com",
+                    "port": 465,
+                    "username": "newuser@example.com",
+                    "password": "newpass",
+                    "use_tls": False,
+                },
+            )
+        assert response.status_code == 200
+
+
+# ── DELETE /smtp-config ───────────────────────────────────────────────────────
+
+
+class TestDeleteSmtpConfig:
+    async def test_deletes_existing_config(self, auth_client, mock_db):
+        existing = _make_smtp_config()
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(existing))
+        response = await auth_client.delete("/api/v1/users/smtp-config")
+        assert response.status_code == 204
+        mock_db.delete.assert_awaited_once_with(existing)
+
+    async def test_no_config_is_noop(self, auth_client, mock_db):
+        mock_db.execute = AsyncMock(return_value=_scalar_one_or_none(None))
+        response = await auth_client.delete("/api/v1/users/smtp-config")
+        assert response.status_code == 204
+        mock_db.delete.assert_not_awaited()
diff --git a/backend/tests/unit/test_version_endpoint.py b/backend/tests/unit/test_version_endpoint.py
new file mode 100644
index 0000000..633aef5
--- /dev/null
+++ b/backend/tests/unit/test_version_endpoint.py
@@ -0,0 +1,42 @@
+"""
+Unit tests for the version endpoint (api/v1/endpoints/version.py).
+"""
+
+import pytest
+from httpx import AsyncClient, ASGITransport
+
+from app.main import create_application
+
+
+@pytest.fixture
+def app():
+    return create_application()
+
+
+class TestVersionEndpoint:
+    async def test_get_version_returns_200(self, app):
+        transport = ASGITransport(app=app)
+        async with AsyncClient(transport=transport, base_url="http://test") as client:
+            response = await client.get("/api/v1/version")
+        assert response.status_code == 200
+
+    async def test_get_version_has_version_key(self, app):
+        transport = ASGITransport(app=app)
+        async with AsyncClient(transport=transport, base_url="http://test") as client:
+            response = await client.get("/api/v1/version")
+        data = response.json()
+        assert "version" in data
+
+    async def test_get_version_has_build_date_key(self, app):
+        transport = ASGITransport(app=app)
+        async with AsyncClient(transport=transport, base_url="http://test") as client:
+            response = await client.get("/api/v1/version")
+        data = response.json()
+        assert "build_date" in data
+
+    async def test_version_is_string_or_none(self, app):
+        transport = ASGITransport(app=app)
+        async with AsyncClient(transport=transport, base_url="http://test") as client:
+            response = await client.get("/api/v1/version")
+        data = response.json()
+        assert isinstance(data["version"], str) or data["version"] is None
diff --git a/docs/TODO.md b/docs/TODO.md
index 62c4a05..fe1600b 100644
--- a/docs/TODO.md
+++ b/docs/TODO.md
@@ -4,6 +4,8 @@ Comprehensive task breakdown for repository improvements and production readines
 
 ## ✅ Recently Completed
 
+- [x] **Expanded backend test coverage**: Added 150 new unit tests across 10 new test files, increasing the backend test count from 361 to 511. New coverage includes `core/gdpr.py`, `utils/gmail_labels.py`, `services/notification_service.py`, `services/auth_service.py`, and API endpoints for auth, users, notifications, processing-runs/logs, app-settings, and version.
+
 - [x] **Improved test coverage for `mail_processor.py`**: Added 46 new unit tests covering POP3 connection testing, POP3 email fetching, IMAP edge cases, email forwarding (STARTTLS/SSL), and `fetch_emails`/`test_connection` routing. Coverage increased from ~42% to 98%.
 
 - [x] **Log noise reduction**: Suppressed `ignored untagged response` INFO messages from `aioimaplib` in Celery workers (set logger to WARNING). Eliminated repeated `file_cache is only supported with oauth2client<4.0.0` warnings from the Gmail API client by passing `cache_discovery=False` to `googleapiclient.discovery.build()`.