'airflow tasks tests' for mapped tasks with dependencies

### Apache Airflow version Other Airflow 2/3 version (please specify below) ### If "Other Airflow 2/3 version" selected, which one? 3.0.6 ### What happened? I have a simple dag where one map task depends on a single task: when running `airflow task tests`: ```bash airflow tasks test problem_dag multiply_by_two --map-index 0 -t '{"number":2}' ``` I get an error saying that the xcoms for `get_numbers` is not found so its defaulting to None, even thought I am testing `multiply_by_two` and provide params for it. ```bash 2025-10-21 13:51:54 [error ] XCom not found [airflow.sdk.api.client] dag_id=problem_dag detail={'detail': {'reason': 'not_found', 'message': "XCom with key='return_value' map_index=-1 not found for task 'get_numbers' in DAG run '__airflow_temporary_run_2025-10-21T13:51:52.789707+00:00__' of 'problem_dag'"}} key=return_value map_index=None run_id=__airflow_temporary_run_2025-10-21T13:51:52.789707+00:00__ status_code=404 task_id=get_numbers 2025-10-21 13:51:54 [warning ] No XCom value found; defaulting to None. [task] dag_id=problem_dag key=return_value map_index=None run_id=__airflow_temporary_run_2025-10-21T13:51:52.789707+00:00__ task_id=get_numbers ``` which than fails ```bash │ /home/airflow/.local/lib/python3.11/site-packages/airflow/sdk/definitions/xcom_arg.py:596 in _ │ │ │ │ 593 │ if xcom_arg.operator.is_mapped: │ │ 594 │ │ # TODO: How to tell if all the upstream TIs finished? │ │ 595 │ │ pass │ │ ❱ 596 │ return (upstream_map_indexes.get(task_id) or 1) * len(resolved_val) ``` with ``` TypeError: object of type 'NoneType' has no len() ``` The full logs can be found here: [log.txt](https://github.com/user-attachments/files/23022615/log.txt) ### Wh…