Raise SmartDeviceException on invalid config dicts (#640)

Co-authored-by: J. Nick Koston <nick@koston.org>

kasa/deviceconfig.py

@@ -37,11 +37,16 @@ def _dataclass_from_dict(klass, in_val):
         fieldtypes = {f.name: f.type for f in fields(klass)}
         val = {}
         for dict_key in in_val:
-            if dict_key in fieldtypes and hasattr(fieldtypes[dict_key], "from_dict"):
-                val[dict_key] = fieldtypes[dict_key].from_dict(in_val[dict_key])
+            if dict_key in fieldtypes:
+                if hasattr(fieldtypes[dict_key], "from_dict"):
+                    val[dict_key] = fieldtypes[dict_key].from_dict(in_val[dict_key])
+                else:
+                    val[dict_key] = _dataclass_from_dict(
+                        fieldtypes[dict_key], in_val[dict_key]
+                    )
             else:
-                val[dict_key] = _dataclass_from_dict(
-                    fieldtypes[dict_key], in_val[dict_key]
+                raise SmartDeviceException(
+                    f"Cannot create dataclass from dict, unknown key: {dict_key}"
                 )
         return klass(**val)
     else:
@@ -173,6 +178,8 @@ class DeviceConfig:
         return _dataclass_to_dict(self)
 
     @staticmethod
-    def from_dict(cparam_dict: Dict[str, Dict[str, str]]) -> "DeviceConfig":
+    def from_dict(config_dict: Dict[str, Dict[str, str]]) -> "DeviceConfig":
         """Return device config from dict."""
-        return _dataclass_from_dict(DeviceConfig, cparam_dict)
+        if isinstance(config_dict, dict):
+            return _dataclass_from_dict(DeviceConfig, config_dict)
+        raise SmartDeviceException(f"Invalid device config data: {config_dict}")

kasa/tests/test_deviceconfig.py

@@ -2,6 +2,7 @@ from json import dumps as json_dumps
 from json import loads as json_loads
 
 import aiohttp
+import pytest
 
 from kasa.credentials import Credentials
 from kasa.deviceconfig import (
@@ -10,6 +11,7 @@ from kasa.deviceconfig import (
     DeviceFamilyType,
     EncryptType,
 )
+from kasa.exceptions import SmartDeviceException
 
 
 async def test_serialization():
@@ -21,6 +23,19 @@ async def test_serialization():
     assert config == config2
 
 
+@pytest.mark.parametrize(
+    ("input_value", "expected_msg"),
+    [
+        ({"Foo": "Bar"}, "Cannot create dataclass from dict, unknown key: Foo"),
+        ("foobar", "Invalid device config data: foobar"),
+    ],
+    ids=["invalid-dict", "not-dict"],
+)
+def test_deserialization_errors(input_value, expected_msg):
+    with pytest.raises(SmartDeviceException, match=expected_msg):
+        DeviceConfig.from_dict(input_value)
+
+
 async def test_credentials_hash():
     config = DeviceConfig(
         host="Foo",