fix(plan): fix the error that won't save the subtask state in session management (agentscope-ai#863)

Author: Young198902

src/agentscope/plan/_plan_model.py

@@ -39,7 +39,6 @@ class SubTask(BaseModel):
     state: Literal["todo", "in_progress", "done", "abandoned"] = Field(
         description="The state of the subtask.",
         default="todo",
-        exclude=True,
     )
     created_at: str = Field(
         description="The time the subtask was created.",

tests/plan_test.py

@@ -326,12 +326,14 @@ async def test_serialization(self) -> None:
                                 "name": "1",
                                 "description": "1",
                                 "expected_outcome": "1",
+                                "state": "todo",
                                 "created_at": subtasks[0].created_at,
                             },
                             {
                                 "name": "2",
                                 "description": "2",
                                 "expected_outcome": "2",
+                                "state": "todo",
                                 "created_at": subtasks[1].created_at,
                             },
                         ],