test: add pyleak for task and event loop block detections (#8802)

* test: add pyleak for task and event loop block detections

* test: add pyleak for task and event loop block detections

* ci: add env variables for verbose logging

* chore: dummy sleep to shwocase error

* chore: dummy sleep to showcase error

* chore: remove dummy sleep

src/backend/tests/integration/components/helpers/test_parse_json_data.py

@@ -3,7 +3,9 @@ from langflow.components.processing.parse_json_data import ParseJSONDataComponen
 from langflow.schema import Data
 
 from tests.integration.components.mock_components import TextToData
-from tests.integration.utils import ComponentInputHandle, run_single_component
+from tests.integration.utils import ComponentInputHandle, pyleak_marker, run_single_component
+
+pytestmark = pyleak_marker()
 
 
 async def test_from_data():

src/backend/tests/integration/components/inputs/test_chat_input.py

@@ -2,7 +2,9 @@ from langflow.components.input_output import ChatInput
 from langflow.memory import aget_messages
 from langflow.schema.message import Message
 
-from tests.integration.utils import run_single_component
+from tests.integration.utils import pyleak_marker, run_single_component
+
+pytestmark = pyleak_marker()
 
 
 async def test_default():

src/backend/tests/integration/components/inputs/test_text_input.py

@@ -1,7 +1,9 @@
 from langflow.components.input_output import TextInputComponent
 from langflow.schema.message import Message
 
-from tests.integration.utils import run_single_component
+from tests.integration.utils import pyleak_marker, run_single_component
+
+pytestmark = pyleak_marker()
 
 
 async def test_text_input():

src/backend/tests/integration/components/prompts/test_prompt.py

@@ -1,7 +1,9 @@
 from langflow.components.processing import PromptComponent
 from langflow.schema.message import Message
 
-from tests.integration.utils import run_single_component
+from tests.integration.utils import pyleak_marker, run_single_component
+
+pytestmark = pyleak_marker()
 
 
 async def test():

src/backend/tests/integration/conftest.py

@@ -4,3 +4,7 @@ import pytest
 @pytest.fixture(autouse=True)
 def _start_app(client):
     pass
+
+
+def pytest_configure(config):
+    config.addinivalue_line("markers", "no_leaks: detect asyncio task leaks, thread leaks, and event loop blocking")

src/backend/tests/integration/flows/test_basic_prompting.py

@@ -3,9 +3,10 @@ from langflow.components.processing import PromptComponent
 from langflow.graph import Graph
 from langflow.schema.message import Message
 
-from tests.integration.utils import run_flow
+from tests.integration.utils import pyleak_marker, run_flow
 
 
+@pyleak_marker()
 async def test_simple_no_llm():
     graph = Graph()
     flow_input = graph.add_component(ChatInput())

src/backend/tests/integration/utils.py

@@ -3,6 +3,7 @@ import os
 import uuid
 from typing import Any
 
+import pytest
 import requests
 from astrapy.admin import parse_api_endpoint
 from langflow.api.v1.schemas import InputValueRequest
@@ -187,3 +188,11 @@ def build_component_instance_for_tests(version: str, module: str, file_name: str
     component = download_component_from_github(module, file_name, version)
     cc_class = eval_custom_component_code(component._code)
     return cc_class(**kwargs), component._code
+
+
+def pyleak_marker(**extra_args):
+    default_args = {
+        "enable_task_creation_tracking": True,  # log task creation stacks
+        "thread_name_filter": r"^(?!asyncio_\d+$).*",  # exclude `asyncio_{num}` threads
+    }
+    return pytest.mark.no_leaks(**default_args, **extra_args)