address backend security and test suggestions

backend/app/tests/test_main_polling.py

@@ -0,0 +1,60 @@
+import asyncio
+from types import SimpleNamespace
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+
+class TestNextSleepSeconds:
+    def test_uses_shortest_enabled_source_interval_without_db_query(self):
+        from app.main import _next_sleep_seconds
+
+        slow = SimpleNamespace(polling_interval=30)
+        fast = SimpleNamespace(polling_interval=5)
+
+        with patch("app.main.SessionLocal") as mock_session:
+            result = _next_sleep_seconds(enabled_sources=[slow, fast])
+
+        assert result == 300
+        mock_session.assert_not_called()
+
+    def test_respects_min_sleep(self):
+        from app.main import _next_sleep_seconds
+
+        source = SimpleNamespace(polling_interval=0)
+
+        assert _next_sleep_seconds(min_sleep=120, enabled_sources=[source]) == 3600
+
+    def test_queries_database_when_sources_not_supplied(self):
+        from app.main import _next_sleep_seconds
+
+        source = SimpleNamespace(polling_interval=2)
+        mock_db = MagicMock()
+        mock_db.query.return_value.filter.return_value.all.return_value = [source]
+
+        with patch("app.main.SessionLocal", return_value=mock_db):
+            result = _next_sleep_seconds()
+
+        assert result == 120
+        mock_db.close.assert_called_once()
+
+    def test_database_exception_falls_back_to_one_hour(self):
+        from app.main import _next_sleep_seconds
+
+        with patch("app.main.SessionLocal", side_effect=RuntimeError("db unavailable")):
+            assert _next_sleep_seconds() == 3600
+
+
+@pytest.mark.asyncio
+async def test_scheduled_imap_polling_sleep_exception_falls_back_then_cancels():
+    from app.main import scheduled_imap_polling
+
+    with (
+        patch("app.main._poll_all_enabled_sources", return_value=[]),
+        patch("app.main._next_sleep_seconds", return_value=60),
+        patch(
+            "app.main.asyncio.sleep",
+            side_effect=[RuntimeError("sleep failed"), asyncio.CancelledError()],
+        ),
+    ):
+        await scheduled_imap_polling()