IWF-921 Add converter specifically for binary/null decoding

Author: Nathan Givens

iwf/object_encoder.py

@@ -228,8 +228,8 @@ def __init__(self) -> None:
         super().__init__(*DefaultPayloadConverter.default_encoding_payload_converters)
 
 
-class BinaryNullPayloadConverter(EncodingPayloadConverter):
-    """Converter for 'binary/null' payloads supporting None values."""
+class UnsetPayloadConverter(EncodingPayloadConverter):
+    """Converter for 'unset' payloads supporting None values."""
 
     @property
     def encoding(self) -> Union[str, Unset]:
@@ -253,6 +253,15 @@ def from_payload(
         return None
 
 
+class BinaryNullPayloadConverter(UnsetPayloadConverter):
+    """Converter for 'binary/null' payloads supporting None values."""
+
+    @property
+    def encoding(self) -> Union[str, Unset]:
+        """See base class."""
+        return "binary/null"
+
+
 class BinaryPlainPayloadConverter(EncodingPayloadConverter):
     """Converter for 'binary/plain' payloads supporting bytes values."""
 
@@ -533,6 +542,7 @@ def decode(
 
 
 DefaultPayloadConverter.default_encoding_payload_converters = (
+    UnsetPayloadConverter(),
     BinaryNullPayloadConverter(),
     BinaryPlainPayloadConverter(),
     JSONPlainPayloadConverter(),