feat: add early Telegram anti-flood guard

tests/test_update_antiflood_middleware.py

@@ -0,0 +1,63 @@
+import unittest
+from types import SimpleNamespace
+from unittest.mock import AsyncMock, patch
+
+from bot.middlewares.update_antiflood import RateLimitRule, UpdateAntiFloodMiddleware
+
+
+def _settings(**overrides):
+    base = {
+        "REDIS_URL": None,
+        "REDIS_KEY_PREFIX": "test-shop",
+        "TELEGRAM_ANTIFLOOD_ENABLED": True,
+        "TELEGRAM_ANTIFLOOD_WINDOW_SECONDS": 60,
+        "TELEGRAM_ANTIFLOOD_MAX_UPDATES_PER_WINDOW": 180,
+    }
+    base.update(overrides)
+    return SimpleNamespace(**base)
+
+
+def _message_update(*, user_id=42, chat_id=42, chat_type="private", text="hello"):
+    return SimpleNamespace(
+        event_type="message",
+        message=SimpleNamespace(
+            from_user=SimpleNamespace(id=user_id),
+            chat=SimpleNamespace(id=chat_id, type=chat_type),
+            text=text,
+        ),
+        callback_query=None,
+        inline_query=None,
+    )
+
+
+class UpdateAntiFloodMiddlewareTests(unittest.IsolatedAsyncioTestCase):
+    async def test_extreme_update_flood_is_dropped_before_handler(self):
+        middleware = UpdateAntiFloodMiddleware(
+            _settings(),
+            default_rule=RateLimitRule(window_seconds=60, max_events=2),
+        )
+        handler = AsyncMock(return_value="ok")
+        event = _message_update()
+
+        with patch("bot.middlewares.update_antiflood.get_redis", AsyncMock(return_value=None)):
+            self.assertEqual(await middleware(handler, event, {}), "ok")
+            self.assertEqual(await middleware(handler, event, {}), "ok")
+            self.assertIsNone(await middleware(handler, event, {}))
+
+        self.assertEqual(handler.await_count, 2)
+
+    async def test_antiflood_can_be_disabled(self):
+        middleware = UpdateAntiFloodMiddleware(
+            _settings(TELEGRAM_ANTIFLOOD_ENABLED=False),
+            default_rule=RateLimitRule(window_seconds=60, max_events=0),
+        )
+        handler = AsyncMock(return_value="ok")
+
+        with patch("bot.middlewares.update_antiflood.get_redis", AsyncMock(return_value=None)):
+            self.assertEqual(await middleware(handler, _message_update(), {}), "ok")
+
+        handler.assert_awaited_once()
+
+
+if __name__ == "__main__":
+    unittest.main()