[BUG] Playwright fixture hangs on teardown with pytest-flask #187

markhobson · 2023-09-30T13:21:55Z

When using playwright-pytest in conjunction with pytest-flask the playwright fixture can hang on teardown.

See markhobson/playwright-pytest-bug for a reproducible example.

Notice the two tests and their fixtures:

def test_page(page: Page):
def test_server_and_page(live_server: LiveServer, page: Page):

Running these tests results in the following output:

$ pytest --setup-show
========================================================================== test session starts ==========================================================================
platform linux -- Python 3.10.12, pytest-7.4.2, pluggy-1.3.0
rootdir: /home/mark/Projects/mark/playwright-pytest-bug
plugins: flask-1.2.0, base-url-2.0.0, playwright-0.4.2
collected 2 items                                                                                                                                                       

tests/test_browser.py 
SETUP    S base_url
SETUP    S _verify_url (fixtures used: base_url)
SETUP    S pytestconfig
SETUP    S delete_output_dir (fixtures used: pytestconfig)
SETUP    S browser_type_launch_args (fixtures used: pytestconfig)
SETUP    S playwright
SETUP    S browser_name['chromium']
SETUP    S browser_type (fixtures used: browser_name, playwright)
SETUP    S launch_browser (fixtures used: browser_type, browser_type_launch_args)
SETUP    S browser (fixtures used: launch_browser)
SETUP    S device (fixtures used: pytestconfig)
SETUP    S browser_context_args (fixtures used: base_url, device, playwright, pytestconfig)
        SETUP    F monkeypatch
        SETUP    F _configure_application (fixtures used: monkeypatch)
        SETUP    F _monkeypatch_response_class (fixtures used: monkeypatch)
        SETUP    F _push_request_context
        SETUP    F context (fixtures used: browser, browser_context_args, pytestconfig)
        SETUP    F page (fixtures used: context)
        tests/test_browser.py::test_page[chromium] (fixtures used: _configure_application, _monkeypatch_response_class, _push_request_context, _verify_url, base_url, browser, browser_context_args, browser_name, browser_type, browser_type_launch_args, context, delete_output_dir, device, launch_browser, monkeypatch, page, playwright, pytestconfig, request).
        TEARDOWN F page
        TEARDOWN F context
        TEARDOWN F _push_request_context
        TEARDOWN F _monkeypatch_response_class
        TEARDOWN F _configure_application
        TEARDOWN F monkeypatch
SETUP    S app
SETUP    S live_server (fixtures used: app, pytestconfig)
        SETUP    F monkeypatch
        SETUP    F _configure_application (fixtures used: monkeypatch)
        SETUP    F _monkeypatch_response_class (fixtures used: monkeypatch)
        SETUP    F _push_request_context
        SETUP    F context (fixtures used: browser, browser_context_args, pytestconfig)
        SETUP    F page (fixtures used: context)
        tests/test_browser.py::test_server_and_page[chromium] (fixtures used: _configure_application, _monkeypatch_response_class, _push_request_context, _verify_url, app, base_url, browser, browser_context_args, browser_name, browser_type, browser_type_launch_args, context, delete_output_dir, device, launch_browser, live_server, monkeypatch, page, playwright, pytestconfig, request).
        TEARDOWN F page
        TEARDOWN F context
        TEARDOWN F _push_request_context
        TEARDOWN F _monkeypatch_response_class
        TEARDOWN F _configure_application
        TEARDOWN F monkeypatch
TEARDOWN S browser_context_args
TEARDOWN S device
TEARDOWN S browser
TEARDOWN S launch_browser
TEARDOWN S browser_type
TEARDOWN S browser_name['chromium']

It then hangs. After CTRL+C it terminates with:

^C
TEARDOWN S playwright

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! KeyboardInterrupt !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
/usr/lib/python3.10/selectors.py:469: KeyboardInterrupt
(to show a full traceback on KeyboardInterrupt use --full-trace)
========================================================================== 2 passed in 11.52s ===========================================================================
Exception ignored in: <function BaseSubprocessTransport.__del__ at 0x7f92cc28dfc0>
Traceback (most recent call last):
  File "/usr/lib/python3.10/asyncio/base_subprocess.py", line 126, in __del__
  File "/usr/lib/python3.10/asyncio/base_subprocess.py", line 104, in close
  File "/usr/lib/python3.10/asyncio/unix_events.py", line 547, in close
  File "/usr/lib/python3.10/asyncio/unix_events.py", line 571, in _close
  File "/usr/lib/python3.10/asyncio/base_events.py", line 753, in call_soon
  File "/usr/lib/python3.10/asyncio/base_events.py", line 515, in _check_closed
RuntimeError: Event loop is closed

The order of tests and fixtures appears significant. Injecting both fixtures into both tests is fine, as is injecting just page into both tests.

As an interaction between pytest-flask and playwright-pytest it's hard to pinpoint in which project the problem lies, but as it's the teardown of the playwright fixture that is hanging, I've raised this issue here.

The text was updated successfully, but these errors were encountered:

mxschmitt · 2023-10-09T16:40:23Z

Short investigation:

Its hanging here:

https://github.com/microsoft/playwright-python/blob/0e92fbc2cceba0551305f2e36f75f9b71f5d5b6e/playwright/_impl/_connection.py#L276-L277

I was not able to find out the root cause. Since this is the first bug report related to this, I'll mark it as p3-collecting-feedback.

iloveitaly · 2025-03-31T13:50:55Z

I'm running into a similar problem, not using pytest-flask but I have a subprocess running uvicorn running a fastapi application, which is most likely a similar situation.

Here's what is happening (sometimes, consistently right now, but seems to stop happening in some scenarios which i cannot yet identify).

Run pytest
Hangs
Ctrl+c
Still hanging
Ctrl+c again, quits

Step #3 (I have a uvicorn server running here, still trying to determine if that is part of the problem):

D venv ❯ 
current_dir=$(pwd)
ps -eo pid,command | awk -v dir="$current_dir" '$2 ~ /python/ && system("lsof -p " $1 " 2>/dev/null | grep -q " dir) == 0 {print $1}' | xargs -I{} sudo py-spy dump --pid {}
Password:
Process 93226: /Users/mike/Projects/cosma/cosma/.venv/bin/python3 /Users/mike/Projects/cosma/cosma/.venv/bin/pytest
Python v3.13.2 (/Users/mike/.local/share/mise/installs/python/3.13.2/bin/python3.13)

Thread 0x209654840 (idle): "MainThread"
    select (selectors.py:548)
    _run_once (asyncio/base_events.py:2002)
    run_forever (asyncio/base_events.py:683)
    run_until_complete (asyncio/base_events.py:712)
    greenlet_main (playwright/sync_api/_context_manager.py:56)
Thread 0x311007000 (active): "asyncio-waitpid-1"
    _do_waitpid (asyncio/unix_events.py:1443)
    run (threading.py:992)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)
Thread 0x312013000 (active): "asyncio_0"
    _worker (concurrent/futures/thread.py:90)
    run (threading.py:992)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)
Error: Failed to open process - check if it is running.
Reason: Operation not permitted (os error 1)
Reason: Operation not permitted (os error 1)
Process 93995: /Users/mike/Projects/cosma/cosma/.venv/bin/python3 -B -P -Wignore::DeprecationWarning -Wignore:ResourceWarning -c from multiprocessing.resource_tracker import main;main(18)
Python v3.13.2 (/Users/mike/.local/share/mise/installs/python/3.13.2/bin/python3.13)

Thread 0x209654840 (active): "MainThread"
    main (multiprocessing/resource_tracker.py:243)
    <module> (<string>:1)
Process 94478: /Users/mike/Projects/cosma/cosma/.venv/bin/python3 -B -P -Wignore::DeprecationWarning -Wignore:ResourceWarning -c from multiprocessing.spawn import spawn_main; spawn_main(tracker_fd=21, pipe_handle=25) --multiprocessing-fork
Python v3.13.2 (/Users/mike/.local/share/mise/installs/python/3.13.2/bin/python3.13)

Thread 0x209654840 (active): "MainThread"
    run (asyncio/runners.py:118)
    run (asyncio/runners.py:195)
    run (uvicorn/server.py:66)
    run (uvicorn/main.py:579)
    run_server (server.py:96)
    run (multiprocessing/process.py:108)
    _bootstrap (multiprocessing/process.py:313)
    _main (multiprocessing/spawn.py:135)
    spawn_main (multiprocessing/spawn.py:122)
    <module> (<string>:1)
Thread 0x16ECA3000 (idle): "AnyIO worker thread"
    wait (threading.py:359)
    get (queue.py:202)
    run (anyio/_backends/_asyncio.py:956)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)
Thread 0x16FCAF000 (idle): "AnyIO worker thread"
    wait (threading.py:359)
    get (queue.py:202)
    run (anyio/_backends/_asyncio.py:956)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)
Thread 0x170CBB000 (idle): "AnyIO worker thread"
    wait (threading.py:359)
    get (queue.py:202)
    run (anyio/_backends/_asyncio.py:956)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)
Thread 0x171CC7000 (idle): "AnyIO worker thread"
    wait (threading.py:359)
    get (queue.py:202)
    run (anyio/_backends/_asyncio.py:956)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)
Thread 0x172CD3000 (idle): "AnyIO worker thread"
    wait (threading.py:359)
    get (queue.py:202)
    run (anyio/_backends/_asyncio.py:956)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)
Thread 0x173CDF000 (idle): "AnyIO worker thread"
    wait (threading.py:359)
    get (queue.py:202)
    run (anyio/_backends/_asyncio.py:956)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)
Thread 0x174CEB000 (idle): "AnyIO worker thread"
    wait (threading.py:359)
    get (queue.py:202)
    run (anyio/_backends/_asyncio.py:956)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)
Thread 0x175CF7000 (idle): "AnyIO worker thread"
    wait (threading.py:359)
    get (queue.py:202)
    run (anyio/_backends/_asyncio.py:956)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)
Thread 0x176D03000 (idle): "AnyIO worker thread"
    wait (threading.py:359)
    get (queue.py:202)
    run (anyio/_backends/_asyncio.py:956)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)
Thread 0x177D0F000 (idle): "AnyIO worker thread"
    wait (threading.py:359)
    get (queue.py:202)
    run (anyio/_backends/_asyncio.py:956)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)
Thread 0x178D1B000 (idle): "AnyIO worker thread"
    wait (threading.py:359)
    get (queue.py:202)
    run (anyio/_backends/_asyncio.py:956)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)
Thread 0x179D27000 (idle): "AnyIO worker thread"
    wait (threading.py:359)
    get (queue.py:202)
    run (anyio/_backends/_asyncio.py:956)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)
Thread 0x17AD33000 (idle): "AnyIO worker thread"
    wait (threading.py:359)
    get (queue.py:202)
    run (anyio/_backends/_asyncio.py:956)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)
Thread 0x17BD3F000 (idle): "AnyIO worker thread"
    wait (threading.py:359)
    get (queue.py:202)
    run (anyio/_backends/_asyncio.py:956)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)

Here's step #4:

D venv ❯ 
current_dir=$(pwd)
ps -eo pid,command | awk -v dir="$current_dir" '$2 ~ /python/ && system("lsof -p " $1 " 2>/dev/null | grep -q " dir) == 0 {print $1}' | xargs -I{} sudo py-spy dump --pid {}
Password:
Process 93226: /Users/mike/Projects/cosma/cosma/.venv/bin/python3 /Users/mike/Projects/cosma/cosma/.venv/bin/pytest
Python v3.13.2 (/Users/mike/.local/share/mise/installs/python/3.13.2/bin/python3.13)

Thread 0x209654840 (active+gil): "MainThread"
    _sync (playwright/_impl/_sync_base.py:113)
    stop (playwright/sync_api/_generated.py:15201)
    on_will_close_browser_context (pytest_playwright/pytest_playwright.py:577)
    _close_wrapper (pytest_playwright/pytest_playwright.py:348)
    new_context (pytest_playwright/pytest_playwright.py:358)
    _teardown_yield_fixture (_pytest/fixtures.py:907)
    finish (_pytest/fixtures.py:1021)
    teardown_exact (_pytest/runner.py:546)
    pytest_sessionfinish (_pytest/runner.py:107)
    _multicall (pluggy/_callers.py:103)
    _hookexec (pluggy/_manager.py:120)
    __call__ (pluggy/_hooks.py:513)
    wrap_session (_pytest/main.py:318)
    pytest_cmdline_main (_pytest/main.py:330)
    _multicall (pluggy/_callers.py:103)
    _hookexec (pluggy/_manager.py:120)
    __call__ (pluggy/_hooks.py:513)
    main (_pytest/config/__init__.py:175)
    console_main (_pytest/config/__init__.py:201)
    <module> (pytest:10)
Thread 0x312013000 (active): "asyncio_0"
    _worker (concurrent/futures/thread.py:90)
    run (threading.py:992)
    _bootstrap_inner (threading.py:1041)
    _bootstrap (threading.py:1012)
Process 93995: /Users/mike/Projects/cosma/cosma/.venv/bin/python3 -B -P -Wignore::DeprecationWarning -Wignore:ResourceWarning -c from multiprocessing.resource_tracker import main;main(18)
Python v3.13.2 (/Users/mike/.local/share/mise/installs/python/3.13.2/bin/python3.13)

Thread 0x209654840 (active): "MainThread"
    main (multiprocessing/resource_tracker.py:243)
    <module> (<string>:1)

And the stack trace on #5:

^C!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! KeyboardInterrupt !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
/Users/mike/.local/share/mise/installs/python/3.13.2/lib/python3.13/selectors.py:548: KeyboardInterrupt
(to show a full traceback on KeyboardInterrupt use --full-trace)
Traceback (most recent call last):
  File "/Users/mike/Projects/cosma/cosma/.venv/bin/pytest", line 10, in <module>
    sys.exit(console_main())
             ~~~~~~~~~~~~^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/_pytest/config/__init__.py", line 201, in console_main
    code = main()
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/_pytest/config/__init__.py", line 175, in main
    ret: ExitCode | int = config.hook.pytest_cmdline_main(config=config)
                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/pluggy/_hooks.py", line 513, in __call__
    return self._hookexec(self.name, self._hookimpls.copy(), kwargs, firstresult)
           ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/pluggy/_manager.py", line 120, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
           ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/pluggy/_callers.py", line 139, in _multicall
    raise exception.with_traceback(exception.__traceback__)
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/pluggy/_callers.py", line 103, in _multicall
    res = hook_impl.function(*args)
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/_pytest/main.py", line 330, in pytest_cmdline_main
    return wrap_session(config, _main)
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/_pytest/main.py", line 318, in wrap_session
    config.hook.pytest_sessionfinish(
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        session=session, exitstatus=session.exitstatus
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/pluggy/_hooks.py", line 513, in __call__
    return self._hookexec(self.name, self._hookimpls.copy(), kwargs, firstresult)
           ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/pluggy/_manager.py", line 120, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
           ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/pluggy/_callers.py", line 139, in _multicall
    raise exception.with_traceback(exception.__traceback__)
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/pluggy/_callers.py", line 122, in _multicall
    teardown.throw(exception)  # type: ignore[union-attr]
    ~~~~~~~~~~~~~~^^^^^^^^^^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/_pytest/logging.py", line 868, in pytest_sessionfinish
    return (yield)
            ^^^^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/pluggy/_callers.py", line 122, in _multicall
    teardown.throw(exception)  # type: ignore[union-attr]
    ~~~~~~~~~~~~~~^^^^^^^^^^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/_pytest/terminal.py", line 893, in pytest_sessionfinish
    result = yield
             ^^^^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/pluggy/_callers.py", line 122, in _multicall
    teardown.throw(exception)  # type: ignore[union-attr]
    ~~~~~~~~~~~~~~^^^^^^^^^^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/_pytest/warnings.py", line 141, in pytest_sessionfinish
    return (yield)
            ^^^^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/pluggy/_callers.py", line 103, in _multicall
    res = hook_impl.function(*args)
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/_pytest/runner.py", line 107, in pytest_sessionfinish
    session._setupstate.teardown_exact(None)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/_pytest/runner.py", line 546, in teardown_exact
    fin()
    ~~~^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/_pytest/fixtures.py", line 1032, in finish
    raise exceptions[0]
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/_pytest/fixtures.py", line 1021, in finish
    fin()
    ~~~^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/_pytest/fixtures.py", line 907, in _teardown_yield_fixture
    next(it)
    ~~~~^^^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/pytest_playwright/pytest_playwright.py", line 358, in new_context
    context.close()
    ~~~~~~~~~~~~~^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/pytest_playwright/pytest_playwright.py", line 348, in _close_wrapper
    _artifacts_recorder.on_will_close_browser_context(context)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/pytest_playwright/pytest_playwright.py", line 577, in on_will_close_browser_context
    context.tracing.stop(path=trace_path)
    ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/playwright/sync_api/_generated.py", line 15201, in stop
    return mapping.from_maybe_impl(self._sync(self._impl_obj.stop(path=path)))
                                   ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/mike/Projects/cosma/cosma/.venv/lib/python3.13/site-packages/playwright/_impl/_sync_base.py", line 113, in _sync
    self._dispatcher_fiber.switch()
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
KeyboardInterrupt

Not sure if this is helpful, but wanted to dump this here in case anyone else is running into a similar problem.

markhobson mentioned this issue Oct 9, 2023

Move Live Server fixtures back to package scope acteng/update-your-capital-schemes#20

Closed

mxschmitt added the p3-collecting-feedback label Oct 9, 2023

mxschmitt changed the title ~~Playwright fixture hangs on teardown~~ [BUG] Playwright fixture hangs on teardown with pytest-flask Oct 9, 2023

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

[BUG] Playwright fixture hangs on teardown with pytest-flask #187

[BUG] Playwright fixture hangs on teardown with pytest-flask #187

markhobson commented Sep 30, 2023

mxschmitt commented Oct 9, 2023

iloveitaly commented Mar 31, 2025

[BUG] Playwright fixture hangs on teardown with pytest-flask #187

[BUG] Playwright fixture hangs on teardown with pytest-flask #187

Comments

markhobson commented Sep 30, 2023

mxschmitt commented Oct 9, 2023

iloveitaly commented Mar 31, 2025