Add lightweight unittest coverage for stability fixes

tests/test_config_check.py

@@ -0,0 +1,20 @@
+import unittest
+
+from services.config_check import validate_cfg
+
+
+class ConfigCheckTests(unittest.TestCase):
+    def test_admin_ids_without_admin_id_is_valid(self):
+        cfg = {
+            "telegram": {
+                "token": "x",
+                "admin_ids": [1, 2],
+            }
+        }
+        errors, warnings = validate_cfg(cfg)
+        self.assertEqual(errors, [])
+        self.assertIsInstance(warnings, list)
+
+
+if __name__ == "__main__":
+    unittest.main()