PYTHON-2263 Respect UuidRepresentation.UNSPECIFIED when parsing $uuid fields in extended JSON (#464)

Author: prashantmital

bson/json_util.py

@@ -449,7 +449,7 @@ def object_hook(dct, json_options=DEFAULT_JSON_OPTIONS):
     if "$code" in dct:
         return _parse_canonical_code(dct)
     if "$uuid" in dct:
-        return _parse_legacy_uuid(dct)
+        return _parse_legacy_uuid(dct, json_options)
     if "$undefined" in dct:
         return None
     if "$numberLong" in dct:
@@ -484,11 +484,14 @@ def _parse_legacy_regex(doc):
     return Regex(pattern, flags)
 
 
-def _parse_legacy_uuid(doc):
+def _parse_legacy_uuid(doc, json_options):
     """Decode a JSON legacy $uuid to Python UUID."""
     if len(doc) != 1:
         raise TypeError('Bad $uuid, extra field(s): %s' % (doc,))
-    return uuid.UUID(doc["$uuid"])
+    if json_options.uuid_representation == UuidRepresentation.UNSPECIFIED:
+        return Binary.from_uuid(uuid.UUID(doc["$uuid"]))
+    else:
+        return uuid.UUID(doc["$uuid"])
 
 
 def _binary_or_uuid(data, subtype, json_options):

test/test_json_util.py

@@ -301,7 +301,11 @@ def test_uuid_uuid_rep_unspecified(self):
         ext_json_str = json_util.dumps(doc)
         self.assertEqual(
             doc, json_util.loads(ext_json_str, json_options=options))
-
+        # $uuid-encoded fields
+        doc = {'uuid': Binary(_uuid.bytes, subtype=4)}
+        ext_json_str = json_util.dumps({'uuid': _uuid})
+        self.assertEqual(
+            doc, json_util.loads(ext_json_str, json_options=options))
 
     def test_binary(self):
         if PY3: