Passing mock to open() crashes Test Run

[Rafq77]

Type: Bug

Behaviour

Test execution fails the test while running Tests that passes MagicMock object to open() method.
First observed while testing fix for: #18030
Was using previously different Test Explorer (littlefoxteam.vscode-python-test-adapter), which had no issues with that test. However testing with previous vscode-python extensions down to "v2023.18.0" showed similar results (failures on that test).

Running the test directly via command line yields no errors (Test runs successfully).

Expected vs. Actual

Expected: Run, Debug Run, Run directly from console have the same output/result
Actual: Debugging and running directly from console end in successful result. Running from within test explorer crashes the test.

Steps to reproduce:

Run following Test via Test Explorer:

from unittest.mock import MagicMock

def test_test_magic_mock_instance():
    tmp = MagicMock()
    openHexOutputFile = open(tmp , "a", encoding="utf-8");
    openHexOutputFile.close()

Run Fails:

Running pytest via command line directly works:

>pytest -k "test_test_magic_mock_instance" test_section.py
================================================= test session starts =================================================
platform win32 -- Python 3.11.2, pytest-7.4.2, pluggy-1.3.0
rootdir: C:\<project_path>\py.build\_tests
plugins: cov-4.1.0, mock-3.11.1
collected 20 items / 19 deselected / 1 selected

test_section.py .                                                                                                [100%]

========================================== 1 passed, 19 deselected in 0.13s ===========================================

Diagnostic data

• Python version (& distribution if applicable, e.g. Anaconda): 3.11.2
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Global
• Value of the python.languageServer setting: Default

Output for Python in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python)

CLIENT: Server listening on port 53060...
Received JSON data in run script
Running pytest with args: ['-p', 'vscode_pytest', '--rootdir', 'c:\\<proj_path>', '--ignore=c:\\<proj_path>/tests/googletest', '--ignore=c:\\<proj_path>/mbed-os', '-s', '--capture=sys', 'c:\\<proj_path>tools\\py.build\\_tests\\test_section.py::test_test_magic_mock_instance']
============================= test session starts =============================
platform win32 -- Python 3.11.2, pytest-7.4.2, pluggy-1.3.0
rootdir: c:\<proj_path>
plugins: cov-4.1.0, mock-3.11.1
collected 1 item

hw\hw.e002\tools\py.build\_tests\test_section.py Traceback (most recent call last):
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\main.py", line 271, in wrap_session
    session.exitstatus = doit(config, session) or 0
                         ^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\main.py", line 325, in _main
    config.hook.pytest_runtestloop(session=session)
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_hooks.py", line 493, in __call__
    return self._hookexec(self.name, self._hookimpls, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_manager.py", line 115, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_callers.py", line 152, in _multicall
    return outcome.get_result()
           ^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_result.py", line 114, in get_result
    raise exc.with_traceback(exc.__traceback__)
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_callers.py", line 77, in _multicall
    res = hook_impl.function(*args)
          ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\main.py", line 350, in pytest_runtestloop
    item.config.hook.pytest_runtest_protocol(item=item, nextitem=nextitem)
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_hooks.py", line 493, in __call__
    return self._hookexec(self.name, self._hookimpls, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_manager.py", line 115, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_callers.py", line 152, in _multicall
    return outcome.get_result()
           ^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_result.py", line 114, in get_result
    raise exc.with_traceback(exc.__traceback__)
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_callers.py", line 77, in _multicall
    res = hook_impl.function(*args)
          ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\runner.py", line 114, in pytest_runtest_protocol
    runtestprotocol(item, nextitem=nextitem)
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\runner.py", line 133, in runtestprotocol
    reports.append(call_and_report(item, "call", log))
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\runner.py", line 226, in call_and_report
    hook.pytest_runtest_logreport(report=report)
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_hooks.py", line 493, in __call__
    return self._hookexec(self.name, self._hookimpls, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_manager.py", line 115, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_callers.py", line 113, in _multicall
    raise exception.with_traceback(exception.__traceback__)
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_callers.py", line 77, in _multicall
    res = hook_impl.function(*args)
          ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\terminal.py", line 599, in pytest_runtest_logreport
    self._tw.write(letter, **markup)
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\_io\terminalwriter.py", line 155, in write
    self._file.write(msg)
OSError: [Errno 9] Bad file descriptor

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\main.py", line 291, in wrap_session
    config.notify_exception(excinfo, config.option)
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\config\__init__.py", line 1108, in notify_exception
    res = self.hook.pytest_internalerror(excrepr=excrepr, excinfo=excinfo)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_hooks.py", line 493, in __call__
    return self._hookexec(self.name, self._hookimpls, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_manager.py", line 115, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_callers.py", line 113, in _multicall
    raise exception.with_traceback(exception.__traceback__)
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_callers.py", line 77, in _multicall
    res = hook_impl.function(*args)
          ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\terminal.py", line 527, in pytest_internalerror
    self.write_line("INTERNALERROR> " + line)
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\terminal.py", line 482, in write_line
    self.ensure_newline()
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\terminal.py", line 448, in ensure_newline
    self._tw.line()
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\_io\terminalwriter.py", line 171, in line
    self.write("\n")
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\_io\terminalwriter.py", line 155, in write
    self._file.write(msg)
OSError: [Errno 9] Bad file descriptor

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "c:\Users\<USER>\.vscode\extensions\ms-python.python-2023.22.0\pythonFiles\vscode_pytest\run_pytest_script.py", line 68, in <module>
    pytest.main(arg_array)
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\config\__init__.py", line 169, in main
    ret: Union[ExitCode, int] = config.hook.pytest_cmdline_main(
                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_hooks.py", line 493, in __call__
    return self._hookexec(self.name, self._hookimpls, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_manager.py", line 115, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_callers.py", line 113, in _multicall
    raise exception.with_traceback(exception.__traceback__)
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_callers.py", line 77, in _multicall
    res = hook_impl.function(*args)
          ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\main.py", line 318, in pytest_cmdline_main
    return wrap_session(config, _main)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\main.py", line 306, in wrap_session
    config.hook.pytest_sessionfinish(
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_hooks.py", line 493, in __call__
    return self._hookexec(self.name, self._hookimpls, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_manager.py", line 115, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python311\Lib\site-packages\pluggy\_callers.py", line 130, in _multicall
    teardown[0].send(outcome)
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\terminal.py", line 858, in pytest_sessionfinish
    self._tw.line("")
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\_io\terminalwriter.py", line 171, in line
    self.write("\n")
  File "C:\Program Files\Python311\Lib\site-packages\_pytest\_io\terminalwriter.py", line 155, in write
    self._file.write(msg)
OSError: [Errno 9] Bad file descriptor
Finished running tests!

User Settings

languageServer: "Jedi"

testing
• pytestArgs: "<placeholder>"
• pytestEnabled: true

experiments
• optInto: ["pythonTestAdapter"]

Extension version: 2023.23.13391009
VS Code version: Code 1.84.2 (1a5daa3a0231a0fbba4f14db7ec463cf99d7768e, 2023-11-09T10:51:52.184Z)
OS version: Windows_NT x64 10.0.19045
Modes:

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-10850H CPU @ 2.70GHz (12 x 2712)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: enabled_on direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: enabled
Load (avg)	undefined
Memory (System)	31.64GB (16.97GB free)
Process Argv	--crash-reporter-id 56596b91-477c-41ad-8393-33181aeda2a8
Screen Reader	no
VM	0%

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[eleanorjboyd]

Will investigate- thanks for the detailed report!

[eleanorjboyd]

Hi! I tried this myself with the code you sent over and successfully got it to run. Could you try running it in the terminal with all these parameters 'python' '-m' 'pytest' '--rootdir', 'c:\\<proj_path>', '--ignore=c:\\<proj_path>/tests/googletest', '--ignore=c:\\<proj_path>/mbed-os', '-s', '--capture=sys', 'c:\\<proj_path>tools\\py.build\\_tests\\test_section.py::test_test_magic_mock_instance' and see what happens? Secondly could you try removing those args and seeing if it works?
Thanks and let me know

[Rafq77]

Thank you for your effort. It looks like the problem doesn't hide within the vscode-extension and I am truly sorry for that.

What I could confirm is that the usage of arguments -s and --capture=sys triggers the mentioned behavior on my side. Additionaly the provided test code was also triggering an error, when the open method was given argument a for appending.

I can execute a successful run when the append on the open() method is replaced with w together with pytest arguments reduced by the misfortunate -s and --capture=sys parameters.

[eleanorjboyd]

No need to apologies! Glad you got it figured out! Happy coding!