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/models/test_taskinstance.py
dag = DAG(
            'test_task_start_end_stats',
            start_date=DEFAULT_DATE,
            end_date=DEFAULT_DATE + datetime.timedelta(days=10),
        )
        op = DummyOperator(task_id='dummy_op', dag=dag)
        dag.create_dagrun(
            run_id='manual__' + DEFAULT_DATE.isoformat(),
            execution_date=DEFAULT_DATE,
            start_date=DEFAULT_DATE,
            state=State.RUNNING,
            external_trigger=False,
        )
        ti = TI(task=op, execution_date=DEFAULT_DATE)
        ti.state = State.RUNNING
        session = settings.Session()
        session.merge(ti)
        session.commit()
        ti._run_raw_task()
        ti.refresh_from_db()
        stats_mock.assert_called_with(f'ti.finish.{dag.dag_id}.{op.task_id}.{ti.state}')
        assert call(f'ti.start.{dag.dag_id}.{op.task_id}') in stats_mock.mock_calls
        assert stats_mock.call_count == 5
    def test_generate_command_default_param(self):