Question: While testing airflow with pytest, i got an Error. # tests/conftest.py import datetime import pytest from airflow.models import DAG @pytest.fixture def test_dag(): return DAG( "test_dag", default_args={ "owner": "airflow", "start_date": datetime.datetime(2025, 4, 5), "end_date": datetime.datetime(2025, 4, 6) }, schedule=datetime.timedelta(days=1) )  # tests/test_instance_context.py import datetime from airflow.models import BaseOperator from airflow.models.dag import DAG from airflow.utils import timezone class SampleDAG(BaseOperator): template_fields = ("_start_date", "_end_date") def __init__(self, start_date, end_date, **kwargs): super().__init__(**kwargs) self._start_date = start_date self._end_date = end_date def execute(self, context): context["ti"].xcom_push(key="start_date", value=self.start_date) context["ti"].xcom_push(key="end_date", value=self.end_date) return context def test_execute(test_dag: DAG): task = SampleDAG( task_id="test", start_date="{{ prev_ds }}", end_date="{{ ds }}", dag=test_dag ) task.run( start_date=test_dag.default_args["start_date"], end_date=test_dag.default_args["end_date"] ) expected_start_date = datetime.datetime(2025, 4, 5, tzinfo=timezone.utc) expected_end_date = datetime.datetime(2025, 4, 6, tzinfo=timezone.utc) assert task.start_date == expected_start_date assert task.end_date == expected_end_date  Test code is passed, but I got an issue here. tests/test_instance_context.py [2025-04-26T12:51:18.289+0000] {taskinstance.py:2604} INFO - Dependencies not met for <TaskInstance: test_dag.test manual__2025-04-05T00:00:00+00:00 [failed]>, dependency 'Task Instance State' FAILED: Task is in the 'failed' state. [2025-04-26T12:51:18.303+0000] {taskinstance.py:2604} INFO - Dependencies not met for <TaskInstance: test_dag.test manual__2025-04-06T00:00:00+00:00 [failed]>, dependency 'Task Instance State' FAILED: Task is in the 'failed' state. .  I want to test task.run to see difference between task.run and task.execute. when I passed jinja variables, then airflow automatically rendering the variables by run method. So, I want to see prev_ds, ds, start_date, end_date is successfully rendered. But I got an error above..

Answer: The error occurs because your SampleDAG operator is failing during execution, which causes subsequent runs to fail due to the task's "failed" state. Let's fix this step by step: Key Issues in Your Code:  Attribute Mismatch: You're using self.start_date and self.end_date in execute() but these attributes don't exist (you defined self._start_date and self._end_date).  Template Rendering: You're passing Jinja templates ({{ prev_ds }}, {{ ds }}) but not properly rendering them before execution.  Task Execution Context: The run() method needs proper context for template rendering.   class SampleDAG(BaseOperator): template_fields = ("_start_date", "_end_date") def __init__(self, start_date, end_date, **kwargs): super().__init__(**kwargs) self._start_date = start_date self._end_date = end_date def execute(self, context): # Use the correct attribute names that match __init__ context["ti"].xcom_push(key="start_date", value=self._start_date) context["ti"].xcom_push(key="end_date", value=self._end_date) return context def test_execute(test_dag: DAG): task = SampleDAG( task_id="test", start_date="{{ prev_ds }}", end_date="{{ ds }}", dag=test_dag ) # Create proper execution context execution_date = test_dag.default_args["start_date"] end_date = test_dag.default_args["end_date"] # Run with proper context task.run( start_date=execution_date, end_date=end_date, execution_date=execution_date, # Needed for template rendering run_id=f"test_run_{execution_date.isoformat()}", ignore_first_depends_on_past=True )