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 = models.DAG(dag_id='test_failure_email')
        task = BashOperator(
            task_id='test_email_alert_with_config',
            dag=dag,
            bash_command='exit 1',
            start_date=DEFAULT_DATE,
            email='to',
        )
        ti = TI(task=task, execution_date=timezone.utcnow())
        opener = mock_open(read_data='template: {{ti.task_id}}')
        with patch('airflow.models.taskinstance.open', opener, create=True):
            try:
                ti.run()
            except AirflowException:
                pass
        (email, title, body), _ = mock_send_email.call_args
        assert email == 'to'
        assert 'template: test_email_alert_with_config' == title
        assert 'template: test_email_alert_with_config' == body
    def test_set_duration(self):