Added ScaleSerializeException

Added Enum and Struct data validation

Author: arjanz

scalecodec/exceptions.py

@@ -37,3 +37,7 @@ class ScaleEncodeException(ValueError):
 
 class ScaleDeserializeException(ValueError):
     pass
+
+
+class ScaleSerializeException(ValueError):
+    pass

scalecodec/types.py

@@ -13,14 +13,16 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import enum
 
 import math
 import struct
 from typing import Union, Optional
 
 from scalecodec.base import ScaleType, ScaleBytes, ScalePrimitive, ScaleTypeDef
 from scalecodec.constants import TYPE_DECOMP_MAX_RECURSIVE
-from scalecodec.exceptions import ScaleEncodeException, ScaleDecodeException, ScaleDeserializeException
+from scalecodec.exceptions import ScaleEncodeException, ScaleDecodeException, ScaleDeserializeException, \
+    ScaleSerializeException
 
 
 class UnsignedInteger(ScalePrimitive):
@@ -230,6 +232,8 @@ def decode(self, data) -> dict:
         return value
 
     def serialize(self, value: dict) -> dict:
+        if value is None:
+            raise ScaleSerializeException('Value cannot be None')
         return {k: obj.value for k, obj in value.items()}
 
     def deserialize(self, value: dict) -> dict:
@@ -400,6 +404,12 @@ def deserialize(self, value: Union[str, dict]) -> tuple:
         if type(value) is str:
             value = {value: None}
 
+        if isinstance(value, enum.Enum):
+            value = {value.name: None}
+
+        if len(list(value.items())) != 1:
+            raise ScaleDeserializeException("Only one variant can be specified for enums")
+
         enum_key, enum_value = list(value.items())[0]
 
         for idx, (variant_name, variant_obj) in enumerate(self.variants.items()):