modify: 解决 message_item result 字段重复序列化问题

tests/test_message_item.py

@@ -1,9 +1,10 @@
 from queue_sqlite.model import MessageItem
+import json
 
 
 class TestMessageItem:
     messageItem = MessageItem(content={"num": 1}, destination="test")
-    
+
     @classmethod
     def test_to_dict(cls):
         print(cls.messageItem.to_dict())
@@ -15,4 +16,46 @@ class TestMessageItem:
     @classmethod
     def test_from_dict(cls):
         messageItem = MessageItem.from_dict(cls.messageItem.to_dict())
-        print(messageItem.to_dict())
+        data = {
+            "id": "ddb66277-503c-4921-8e7f-5091eace49e3",
+            "type": "task",
+            "status": 2,
+            "content": '{"num": 1}',
+            "createtime": "2025-09-12T18:41:08.221531",
+            "updatetime": "2025-09-12T18:41:08.221531",
+            "result": '"{\\"message\\": \\"\\\\u6d4b\\\\u8bd5\\\\u6210\\\\u529f\\"}"',
+            "priority": 1,
+            "source": "client",
+            "destination": "test",
+            "retry_count": 0,
+            "expire_time": "null",
+            "tags": "null",
+            "metadata": "{}",
+        }
+        print(messageItem.to_dict())
+        print(MessageItem.from_dict(data).to_dict())
+
+    @classmethod
+    def test_from_json(cls):
+        json_str = """
+        {
+            "content": {
+                "num": 1
+            },
+            "createtime": "2025-09-12T16:42:50.663248",
+            "destination": "test",
+            "expire_time": null,
+            "id": "b83c3d72-0b06-4c34-ab4f-32d696aa3875",
+            "metadata": {},
+            "priority": 1,
+            "result": "{\"message\": \"\\u6d4b\\u8bd5\\u6210\\u529f\"}",
+            "retry_count": 0,
+            "source": "client",
+            "status": 2,
+            "tags": null,
+            "type": "task",
+            "updatetime": "2025-09-12T16:42:50.663248"
+        }
+        """
+        messageItem = MessageItem.from_dict(json.loads(json_str))
+        print(messageItem.to_json())