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/test_utils/asserts.py
#
#
import logging
import re
import traceback
from collections import Counter
from contextlib import contextmanager
from sqlalchemy import event
import airflow.settings
log = logging.getLogger(__name__)
def assert_equal_ignore_multiple_spaces(case, first, second, msg=None):
    def _trim(s):
        return re.sub(r"\s+", " ", s.strip())
    return case.assertEqual(_trim(first), _trim(second), msg)
class CountQueries:
    """
    Counts the number of queries sent to Airflow Database in a given context.
    Does not support multiple processes. When a new process is started in context, its queries will
    not be included.
    """
    def __init__(self):
        self.result = Counter()
    def __enter__(self):
        event.listen(airflow.settings.engine, "after_cursor_execute", self.after_cursor_execute)
        return self.result
    def __exit__(self, type_, value, tb):
        event.remove(airflow.settings.engine, "after_cursor_execute", self.after_cursor_execute)
        log.debug("Queries count: %d", sum(self.result.values()))
    def after_cursor_execute(self, *args, **kwargs):