With 8.3.3 (as well as the current main, f373974), something like
import pytest
def test_stuff(fixt):
pass
@pytest.fixture
def fixt(request):
yield
# e.g. store screenshots on failures for GUI tests
request.getfixturevalue("tmp_path")results in a rather confusing internal AssertionError from pytest:
============================= test session starts ==============================
collected 1 item
test_cleanup.py .E [100%]
==================================== ERRORS ====================================
_______________________ ERROR at teardown of test_stuff ________________________
request = <SubRequest 'fixt' for <Function test_stuff>>
@pytest.fixture
def fixt(request):
yield
# e.g. store screenshots on failures for GUI tests
> request.getfixturevalue("tmp_path")
test_cleanup.py:12:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
/usr/lib/python3.12/site-packages/_pytest/fixtures.py:532: in getfixturevalue
fixturedef = self._get_active_fixturedef(argname)
/usr/lib/python3.12/site-packages/_pytest/fixtures.py:617: in _get_active_fixturedef
fixturedef.execute(request=subrequest)
/usr/lib/python3.12/site-packages/_pytest/fixtures.py:1094: in execute
request.node.addfinalizer(finalizer)
/usr/lib/python3.12/site-packages/_pytest/nodes.py:391: in addfinalizer
self.session._setupstate.addfinalizer(fin, self)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
self = <_pytest.runner.SetupState object at 0x7457a8320470>
finalizer = functools.partial(<bound method FixtureDef.finish of <FixtureDef argname='tmp_path' scope='function' baseid=''>>, request=<SubRequest 'tmp_path' for <Function test_stuff>>)
node = <Function test_stuff>
def addfinalizer(self, finalizer: Callable[[], object], node: Node) -> None:
"""Attach a finalizer to the given node.
The node must be currently active in the stack.
"""
assert node and not isinstance(node, tuple)
assert callable(finalizer)
> assert node in self.stack, (node, self.stack)
E AssertionError: (<Function test_stuff>, {})
/usr/lib/python3.12/site-packages/_pytest/runner.py:526: AssertionError
=========================== short test summary info ============================
ERROR test_cleanup.py::test_stuff - AssertionError: (<Function test_stuff>, {})
========================== 1 passed, 1 error in 0.04s ==========================
which is here:
|
def addfinalizer(self, finalizer: Callable[[], object], node: Node) -> None: |
|
"""Attach a finalizer to the given node. |
|
|
|
The node must be currently active in the stack. |
|
""" |
|
assert node and not isinstance(node, tuple) |
|
assert callable(finalizer) |
|
assert node in self.stack, (node, self.stack) |
|
self.stack[node][0].append(finalizer) |
This seems similar to what has been reported (and improved) by @petebman here:
and indeed, also requesting tmp_path from the test (after fixt, so it's torn down first) leads to a much better error message:
AssertionError: The fixture value for "tmp_path" is not available. This can happen when the fixture has already been torn down.
From what I can gather, what happens here instead is:
- The test itself does not use tmp_path
- Then fixt requests it during teardown
- That causes pytest to register a new teardown finalizer for tmp_path with the current test node
- But that test node is already gone because it was just torn down
- Thus causing the AssertionError
In the actual context we saw this in qutebrowser, this was made even more difficult to debug:
- For some reason I couldn't track down yet, something in pytest (potentially some __tracebackhide__ in my code?!) decided to just show:
> fixture = self.request.getfixturevalue('take_x11_screenshot')
E AssertionError: [...]without a full traceback.
- Due to parametrization and lots of fixtures involved, the displayed structures were quite big:
AssertionError: (<Function test_sandboxing[disable-seccomp-bpf-True-False-True-You are NOT adequately sandboxed.]>, {<Session exitstatus=<ExitCode.OK: 0> testsfailed=3 testscollected=3>: ([<bound method Node.teardown of <Session exitstatus=<ExitCode.OK: 0> testsfailed=3 testscollected=3>>, functools.partial(<bound method FixtureDef.finish of <FixtureDef argname='check_display' scope='session' baseid='tests'>>, request=<SubRequest 'check_display' for <Function test_sandboxing[enable-all-True-True-True-You are adequately sandboxed.]>>), functools.partial(<bound method FixtureDef.finish of <FixtureDef argname='check_yaml_c_exts' scope='session' baseid='tests'>>, request=<SubRequest 'check_yaml_c_exts' for <Function test_sandboxing[enable-all-True-True-True-You are adequately sandboxed.]>>), functools.partial(<bound method FixtureDef.finish of <FixtureDef argname='fail_on_logging' scope='session' baseid='tests'>>, request=<SubRequest 'fail_on_logging' for <Function test_sandboxing[enable-all-True-True-True-You are adequately sandboxed.]>>), functools.partial(<bound method FixtureDef.finish of <FixtureDef argname='qapp_args' scope='session' baseid='tests'>>, request=<SubRequest 'qapp_args' for <Function test_sandboxing[enable-all-True-True-True-You are adequately sandboxed.]>>), functools.partial(<bound method FixtureDef.finish of <FixtureDef argname='qapp_cls' scope='session' baseid=''>>, request=<SubRequest 'qapp_cls' for <Function test_sandboxing[enable-all-True-True-True-You are adequately sandboxed.]>>), functools.partial(<bound method FixtureDef.finish of <FixtureDef argname='pytestconfig' scope='session' baseid=''>>, request=<SubRequest 'pytestconfig' for <Function test_sandboxing[enable-all-True-True-True-You are adequately sandboxed.]>>), functools.partial(<bound method FixtureDef.finish of <FixtureDef argname='qapp' scope='session' baseid=''>>, request=<SubRequest 'qapp' for <Function test_sandboxing[enable-all-True-True-True-You are adequately sandboxed.]>>), functools.partial(<bound method FixtureDef.finish of <FixtureDef argname='qapp' scope='session' baseid='tests'>>, request=<SubRequest 'qapp' for <Function test_sandboxing[enable-all-True-True-True-You are adequately sandboxed.]>>), functools.partial(<bound method FixtureDef.finish of <FixtureDef argname='server' scope='session' baseid='tests/end2end'>>, request=<SubRequest 'server' for <Function test_sandboxing[enable-all-True-True-True-You are adequately sandboxed.]>>), functools.partial(<bound method FixtureDef.finish of <FixtureDef argname='tmp_path_factory' scope='session' baseid=''>>, request=<SubRequest 'tmp_path_factory' for <Function test_sandboxing[enable-all-True-True-True-You are adequately sandboxed.]>>)], None), <Dir work>: ([<bound method Node.teardown of <Dir work>>], None), <Dir tests>: ([<bound method Node.teardown of <Dir tests>>], None), <Dir end2end>: ([<bound method Node.teardown of <Dir end2end>>], None), <Module test_invocations.py>: ([<bound method Node.teardown of <Module test_invocations.py>>], None)})
- It only happening sometimes (rarely), perhaps because the teardown order was different or something...
With 8.3.3 (as well as the current main, f373974), something like
results in a rather confusing internal AssertionError from pytest:
============================= test session starts ============================== collected 1 item test_cleanup.py .E [100%] ==================================== ERRORS ==================================== _______________________ ERROR at teardown of test_stuff ________________________ request = <SubRequest 'fixt' for <Function test_stuff>> @pytest.fixture def fixt(request): yield # e.g. store screenshots on failures for GUI tests > request.getfixturevalue("tmp_path") test_cleanup.py:12: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ /usr/lib/python3.12/site-packages/_pytest/fixtures.py:532: in getfixturevalue fixturedef = self._get_active_fixturedef(argname) /usr/lib/python3.12/site-packages/_pytest/fixtures.py:617: in _get_active_fixturedef fixturedef.execute(request=subrequest) /usr/lib/python3.12/site-packages/_pytest/fixtures.py:1094: in execute request.node.addfinalizer(finalizer) /usr/lib/python3.12/site-packages/_pytest/nodes.py:391: in addfinalizer self.session._setupstate.addfinalizer(fin, self) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ self = <_pytest.runner.SetupState object at 0x7457a8320470> finalizer = functools.partial(<bound method FixtureDef.finish of <FixtureDef argname='tmp_path' scope='function' baseid=''>>, request=<SubRequest 'tmp_path' for <Function test_stuff>>) node = <Function test_stuff> def addfinalizer(self, finalizer: Callable[[], object], node: Node) -> None: """Attach a finalizer to the given node. The node must be currently active in the stack. """ assert node and not isinstance(node, tuple) assert callable(finalizer) > assert node in self.stack, (node, self.stack) E AssertionError: (<Function test_stuff>, {}) /usr/lib/python3.12/site-packages/_pytest/runner.py:526: AssertionError =========================== short test summary info ============================ ERROR test_cleanup.py::test_stuff - AssertionError: (<Function test_stuff>, {}) ========================== 1 passed, 1 error in 0.04s ==========================which is here:
pytest/src/_pytest/runner.py
Lines 519 to 527 in d0f136f
This seems similar to what has been reported (and improved) by @petebman here:
and indeed, also requesting tmp_path from the test (after fixt, so it's torn down first) leads to a much better error message:
From what I can gather, what happens here instead is:
In the actual context we saw this in qutebrowser, this was made even more difficult to debug:
without a full traceback.