fix: resolve flaky test and JSON config validation

fastapi_traffic/core/config_loader.py

@@ -217,14 +217,14 @@ class ConfigLoader:
 
         return env_vars
 
-    def _load_json_file(self, file_path: Path) -> dict[str, Any]:
+    def _load_json_file(self, file_path: Path) -> Any:
         """Load configuration from a JSON file.
 
         Args:
             file_path: Path to the JSON file.
 
         Returns:
-            Configuration dictionary.
+            Parsed JSON data (could be any JSON type).
 
         Raises:
             ConfigurationError: If the file cannot be read or parsed.
@@ -235,7 +235,7 @@ class ConfigLoader:
 
         try:
             with file_path.open(encoding="utf-8") as f:
-                data: dict[str, Any] = json.load(f)
+                data: Any = json.load(f)
         except json.JSONDecodeError as e:
             msg = f"Invalid JSON in {file_path}: {e}"
             raise ConfigurationError(msg) from e
@@ -350,6 +350,9 @@ class ConfigLoader:
         """
         path = Path(file_path)
         raw_config = self._load_json_file(path)
+        if not isinstance(raw_config, dict):
+            msg = "JSON root must be an object"
+            raise ConfigurationError(msg)
         config_dict = self._validate_and_convert(raw_config, _RATE_LIMIT_FIELD_TYPES)
 
         # Apply overrides

tests/test_algorithms.py

@@ -426,7 +426,8 @@ class TestSlidingWindowCounterAdvanced:
         allowed, _ = await algo.check("precision_key")
         assert not allowed
 
-        await asyncio.sleep(0.5)
+        # Wait for the full window to pass to ensure tokens are fully replenished
+        await asyncio.sleep(1.1)
 
         allowed, _ = await algo.check("precision_key")
         assert allowed