Pytest 7: test_high_number_of_file_descriptors causes next test to fail

[bnavigator]

❓ I'm submitting a ...

• 🐞 bug report
• 🐣 feature request
• ❓ question about the decisions made in the repository

🐞 Describe the bug. What is the current behavior?
When upgrading to pytest 7, the test suite fails with an error for setting up the first test of test_ssl.py, which is usually run after test_server.py::test_high_numer_of_file_descriptors.

💡 To Reproduce

1. Install pytest >= 7.1.1
2. replace --numprocesses=auto in pytest.ini with 1 or delete the flag.
3. Run pytest

💡 Expected behavior
Successful test suite

📋 Details

abuild@skylab:~/rpmbuild/BUILD/cheroot-8.6.0> python3 -m pytest -x -n 1
================================================================================================================================= test session starts ==================================================================================================================================
platform linux -- Python 3.8.12, pytest-7.1.1, pluggy-1.0.0 -- /usr/bin/python3
cachedir: .pytest_cache
rootdir: /home/abuild/rpmbuild/BUILD/cheroot-8.6.0, configfile: pytest.ini, testpaths: cheroot/test/
plugins: forked-1.3.0, xdist-2.5.0, mock-3.6.1
[gw0] linux Python 3.8.12 cwd: /home/abuild/rpmbuild/BUILD/cheroot-8.6.0
[gw0] Python 3.8.12 (default, Aug 31 2021, 01:23:42) [GCC]
gw0 [157]
scheduling tests via LoadScheduling

...
[gw0] [ 64%] PASSED cheroot/test/test_server.py::test_peercreds_unix_sock_with_lookup[file] 
cheroot/test/test_server.py::test_high_number_of_file_descriptors[1024] Exception ignored in: <socket.socket fd=1027, family=AddressFamily.AF_INET6, type=SocketKind.SOCK_STREAM, proto=6, laddr=('::1', 38954, 0, 0), raddr=('::1', 59583, 0, 0)>
Traceback (most recent call last):
  File "/usr/lib/python3.8/site-packages/_pytest/runner.py", line 136, in runtestprotocol
    item.funcargs = None  # type: ignore[attr-defined]
ResourceWarning: unclosed <socket.socket fd=1027, family=AddressFamily.AF_INET6, type=SocketKind.SOCK_STREAM, proto=6, laddr=('::1', 38954, 0, 0), raddr=('::1', 59583, 0, 0)>

[gw0] [ 65%] PASSED cheroot/test/test_server.py::test_high_number_of_file_descriptors[1024] 
cheroot/test/test_server.py::test_high_number_of_file_descriptors[2048] Exception ignored in: <socket.socket fd=2051, family=AddressFamily.AF_INET6, type=SocketKind.SOCK_STREAM, proto=6, laddr=('::1', 35316, 0, 0), raddr=('::1', 44913, 0, 0)>
Traceback (most recent call last):
  File "/usr/lib/python3.8/site-packages/_pytest/runner.py", line 136, in runtestprotocol
    item.funcargs = None  # type: ignore[attr-defined]
ResourceWarning: unclosed <socket.socket fd=2051, family=AddressFamily.AF_INET6, type=SocketKind.SOCK_STREAM, proto=6, laddr=('::1', 35316, 0, 0), raddr=('::1', 44913, 0, 0)>

[gw0] [ 66%] PASSED cheroot/test/test_server.py::test_high_number_of_file_descriptors[2048] 
cheroot/test/test_ssl.py::test_ssl_adapters[builtin] 
[gw0] [ 66%] ERROR cheroot/test/test_ssl.py::test_ssl_adapters[builtin] 

======================================================================================================================================== ERRORS ========================================================================================================================================
_____________________________________________________________________________________________________________________ ERROR at setup of test_ssl_adapters[builtin] _____________________________________________________________________________________________________________________
[gw0] linux -- Python 3.8.12 /usr/bin/python3

cls = <class '_pytest.runner.CallInfo'>, func = <function call_runtest_hook.<locals>.<lambda> at 0x7fd354fec160>, when = 'setup', reraise = (<class '_pytest.outcomes.Exit'>, <class 'KeyboardInterrupt'>)

    @classmethod
    def from_call(
        cls,
        func: "Callable[[], TResult]",
        when: "Literal['collect', 'setup', 'call', 'teardown']",
        reraise: Optional[
            Union[Type[BaseException], Tuple[Type[BaseException], ...]]
        ] = None,
    ) -> "CallInfo[TResult]":
        """Call func, wrapping the result in a CallInfo.
    
        :param func:
            The function to call. Called without arguments.
        :param when:
            The phase in which the function is called.
        :param reraise:
            Exception or exceptions that shall propagate if raised by the
            function, instead of being wrapped in the CallInfo.
        """
        excinfo = None
        start = timing.time()
        precise_start = timing.perf_counter()
        try:
>           result: Optional[TResult] = func()

cls        = <class '_pytest.runner.CallInfo'>
duration   = 0.00038953999955992913
excinfo    = <ExceptionInfo AssertionError('previous item was not torn down properly') tblen=6>
func       = <function call_runtest_hook.<locals>.<lambda> at 0x7fd354fec160>
precise_start = 5120.715909499
precise_stop = 5120.716299039
reraise    = (<class '_pytest.outcomes.Exit'>, <class 'KeyboardInterrupt'>)
result     = None
start      = 1648897978.8972251
stop       = 1648897978.8976173
when       = 'setup'

/usr/lib/python3.8/site-packages/_pytest/runner.py:338: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
/usr/lib/python3.8/site-packages/_pytest/runner.py:259: in <lambda>
    lambda: ihook(item=item, **kwds), when=when, reraise=reraise
        ihook      = <_HookCaller 'pytest_runtest_setup'>
        item       = <Function test_ssl_adapters[builtin]>
        kwds       = {}
/usr/lib/python3.8/site-packages/pluggy/_hooks.py:265: in __call__
    return self._hookexec(self.name, self.get_hookimpls(), kwargs, firstresult)
        argname    = 'item'
        args       = ()
        firstresult = False
        kwargs     = {'item': <Function test_ssl_adapters[builtin]>}
        self       = <_HookCaller 'pytest_runtest_setup'>
/usr/lib/python3.8/site-packages/pluggy/_manager.py:80: in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
        firstresult = False
        hook_name  = 'pytest_runtest_setup'
        kwargs     = {'item': <Function test_ssl_adapters[builtin]>}
        methods    = [<HookImpl plugin_name='nose', plugin=<module '_pytest.nose' from '/usr/lib/python3.8/site-packages/_pytest/nose.py'>>...=None>>, <HookImpl plugin_name='logging-plugin', plugin=<_pytest.logging.LoggingPlugin object at 0x7fd357f1a5e0>>, ...]
        self       = <_pytest.config.PytestPluginManager object at 0x7fd35dbb1b50>
/usr/lib/python3.8/site-packages/_pytest/runner.py:154: in pytest_runtest_setup
    item.session._setupstate.setup(item)
        item       = <Function test_ssl_adapters[builtin]>
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <_pytest.runner.SetupState object at 0x7fd357ecb220>, item = <Function test_ssl_adapters[builtin]>

    def setup(self, item: Item) -> None:
        """Setup objects along the collector chain to the item."""
        needed_collectors = item.listchain()
    
        # If a collector fails its setup, fail its entire subtree of items.
        # The setup is not retried for each item - the same exception is used.
        for col, (finalizers, exc) in self.stack.items():
>           assert col in needed_collectors, "previous item was not torn down properly"
E           AssertionError: previous item was not torn down properly

col        = <Module test_server.py>
exc        = None
finalizers = [<bound method Node.teardown of <Module test_server.py>>]
item       = <Function test_ssl_adapters[builtin]>
needed_collectors = [<Session cheroot-8.6.0 exitstatus=<ExitCode.OK: 0> testsfailed=0 testscollected=157>, <Package test>, <Module test_ssl.py>, <Function test_ssl_adapters[builtin]>]
self       = <_pytest.runner.SetupState object at 0x7fd357ecb220>

/usr/lib/python3.8/site-packages/_pytest/runner.py:482: AssertionError
--------------------------------------------------------------------------------------------- generated xml file: /home/abuild/rpmbuild/BUILD/cheroot-8.6.0/.test-results/pytest/test.xml ----------------------------------------------------------------------------------------------
================================================================================================================================= slowest 10 durations =================================================================================================================================
4.01s call     cheroot/test/test_conn.py::test_HTTP11_Timeout_after_request
3.43s call     cheroot/test/test_conn.py::test_keepalive_conn_management
2.00s call     cheroot/test/test_conn.py::test_HTTP11_Timeout[True]
2.00s call     cheroot/test/test_conn.py::test_HTTP11_Timeout[False]
1.04s call     cheroot/test/test_conn.py::test_invalid_selected_connection
0.60s call     cheroot/test/test_conn.py::test_598
0.60s call     cheroot/test/test_server.py::test_server_interrupt[RuntimeError]
0.60s call     cheroot/test/test_server.py::test_server_interrupt[OSError1]
0.60s call     cheroot/test/test_server.py::test_server_interrupt[OSError0]
0.60s call     cheroot/test/test_server.py::test_server_interrupt[KeyboardInterrupt]
=============================================================================================================================== short test summary info ================================================================================================================================
XFAIL cheroot/test/test_conn.py::test_Chunked_Encoding
  Headers from earlier request leak into the request line for a subsequent request, resulting in 400 instead of 413. See cherrypy/cheroot#69 for details.
XFAIL cheroot/test/test_conn.py::test_598
  Sometimes this test fails due to low timeout. Ref: https://github.com/cherrypy/cherrypy/issues/598
XFAIL cheroot/test/test_core.py::test_large_request
  https://github.com/cherrypy/cheroot/issues/106
ERROR cheroot/test/test_ssl.py::test_ssl_adapters[builtin] - AssertionError: previous item was not torn down properly
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! stopping after 1 failures !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! xdist.dsession.Interrupted: stopping after 1 failures !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
================================================================================================================== 101 passed, 3 xfailed, 1 error in 63.11s (0:01:03) ==================================================================================================================
abuild@skylab:~/rpmbuild/BUILD/cheroot-8.6.0> 

📋 Environment

• Cheroot version: 6.8.0
• CherryPy version: N/A
• Python version: 3.8.12 (+ 3.9 + 3.10)
• OS: openSUSE Tumbleed Linux (Inside openbuildservive VM for rpmbuild)

[webknjaz]

That's an incompatibility of pytest-forked and pytest 7.