### Discussed in https://github.com/apache/airflow/discussions/33345

<div type='discussions-op-text'>

<sup>Originally posted by **vuphamcs** August 11, 2023</sup>
### Description

Is there a variable similar to `prev_start_date_success` but for the previous DAG run’s completion date? The value I’m hoping to retrieve to use within the next DAG run is `2023-08-10 16:04:30`

![image](https://github.com/apache/airflow/assets/1600760/9e2af349-4c3e-47e1-8a1a-9d8827b56f57)


### Use case/motivation

One particular use case is to help guarantee that the next DAG run only queries data that was inserted during the existing DAG run, and not the past DAG run.

```python
prev_ts = context['prev_end_date_success']

sql = f"SELECT * FROM results WHERE created_at > {context['prev_end_date_success']}"
```

### Related issues

_No response_

### Are you willing to submit a 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)
</div>
"""Helper function that asserts `TaskInstances` of a given `task_id` are in a given state."""
        asserts = []
        for ti in dag_run.get_task_instances():
            try:
                expected = expected_states[ti.task_id]
            except KeyError:
                asserts.append(f"Unexpected task id {ti.task_id!r} found, expected {expected_states.keys()}")
                continue
            if ti.state != expected:
                asserts.append(f"Task {ti.task_id!r} has state {ti.state!r} instead of expected {expected!r}")
        if asserts:
            pytest.fail("\n".join(asserts))
    @staticmethod
    def default_kwargs(**kwargs):
        """Default arguments for specific Operator."""
        return kwargs
    def create_dag_run(self) -> DagRun:
        return self.dag.create_dagrun(
            state=DagRunState.RUNNING,
            start_date=self.dag_maker.start_date,
            session=self.dag_maker.session,
            execution_date=self.default_date,
            run_type=DagRunType.MANUAL,
        )
    def create_ti(self, fn, **kwargs) -> TI: