We have flaky scheduler test:


https://github.com/apache/airflow/pull/11659/checks?check_run_id=1279791496#step:6:527


_______________ TestSchedulerJob.test_scheduler_task_start_date ________________

self = <tests.jobs.test_scheduler_job.TestSchedulerJob testMethod=test_scheduler_task_start_date>

    def test_scheduler_task_start_date(self):
        """
        Test that the scheduler respects task start dates that are different from DAG start dates
        """
    
        dagbag = DagBag(dag_folder=os.path.join(settings.DAGS_FOLDER, "no_dags.py"), include_examples=False)
        dag_id = 'test_task_start_date_scheduling'
        dag = self.dagbag.get_dag(dag_id)
        dag.is_paused_upon_creation = False
        dagbag.bag_dag(dag=dag, root_dag=dag)
    
        # Deactivate other dags in this file so the scheduler doesn't waste time processing them
        other_dag = self.dagbag.get_dag('test_start_date_scheduling')
        other_dag.is_paused_upon_creation = True
        dagbag.bag_dag(dag=other_dag, root_dag=other_dag)
    
        dagbag.sync_to_db()
    
        scheduler = SchedulerJob(executor=self.null_exec,
                                 subdir=dag.fileloc,
                                 num_runs=2)
        scheduler.run()
    
        session = settings.Session()
        tiq = session.query(TaskInstance).filter(TaskInstance.dag_id == dag_id)
        ti1s = tiq.filter(TaskInstance.task_id == 'dummy1').all()
        ti2s = tiq.filter(TaskInstance.task_id == 'dummy2').all()
        self.assertEqual(len(ti1s), 0)
>       self.assertEqual(len(ti2s), 2)
E       AssertionError: 1 != 2
tests/jobs/test_scheduler_job.py
clear_db_runs()
        clear_db_pools()
        clear_db_dags()
        clear_db_sla_miss()
        clear_db_import_errors()
        clear_db_jobs()
        clear_db_serialized_dags()
    def setUp(self):
        self.clean_db()
        
        
        self.null_exec = MockExecutor()
    def tearDown(self) -> None:
        self.clean_db()
    def create_test_dag(self, start_date=DEFAULT_DATE, end_date=DEFAULT_DATE + timedelta(hours=1), **kwargs):
        dag = DAG(
            dag_id='test_scheduler_reschedule',
            start_date=start_date,
            
            end_date=end_date,
        )
        dag.clear()
        dag.is_subdag = False
        with create_session() as session:
            orm_dag = DagModel(dag_id=dag.dag_id, is_paused=False)
            session.merge(orm_dag)
            session.commit()
        return dag
    @classmethod
    def setUpClass(cls):