dag.test "mark_success_pattern" could work nicer with dynamically mapped tasks

### Apache Airflow version

Other Airflow 3 version (please specify below)

### If "Other Airflow 3 version" selected, which one?

3.1.2

### What happened?

`Cannot expand for run manual__2026-02-06T19:06:43.772890+00:00; missing upstream values: ['op_args']`

This occurs whenever you run `dag.test()` and provide a `mark_success_pattern` for the upstream task to the dynamic operator. The dynamic task has no input values to map over, and predictably fails.

What could be considered a bug, is the same error still occurs when you ALSO provide a `mark_success_pattern` for the dynamic task itself.

### What you think should happen instead?

I would prefer if the test function were smart enough to check for tasks it should auto-succeed, **including dynamic tasks**, before checking for "missing upstream values."

One difficulty is a task still needs to be generated, but it should be simple enough to generate a single successful mapped task.

(The more I think about this, the more I think it is a feature request and not a bug, but hey 🤷 ).

### How to reproduce

```
from airflow import DAG
from airflow.providers.standard.operators.python import PythonOperator

def generate_list():
return [["item1"], ["item2"], ["item3"]]

def process_item(item):
print(f"Processing {item}")

with DAG(
dag_id="test_dynamic_mapping_dag",
default_args={"owner": "airflow"},
schedule=None,
) as dag:

generate_task = PythonOperator(
task_id="generate_list",
python_callable=generate_list,
)

process_task = PythonOperator.partial(
task_id="process_item",
python_callable=process_item,
).expand(op_args=generate_task.output)

if __name__ == "__main__":
# running the below will understandably fail
# dag.test(mark_success_pattern="generate_list")

# running the below will fail, but arguably should succeed
dag.test(mark_success_pattern="generate_list|process_item")

```

### Operating System

Debian GNU/Linux

### Versions of Apache Airflow Providers

_No response_

### Deployment

Official Apache Airflow Helm Chart

### Deployment details

_No response_

### Anything else?

_No response_

### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [x] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)