"ModuleNotFoundError: No module named 'packaging'" occurs when running unit tests

[saturday06]

Type: Bug

Behaviour

When attempting to run unit tests, the execution aborts with the following exception:

Traceback (most recent call last):
  File "/home/vscode/.vscode-server/extensions/ms-python.python-2025.6.0-linux-x64/python_files/unittestadapter/execution.py", line 15, in <module>
    from packaging.version import Version
ModuleNotFoundError: No module named 'packaging'
Finished running tests!

The python extension version 2025.4.0 works fine.

Steps to reproduce:

1. create unittest

from unittest import TestCase


class TestFoo(TestCase):
    def test_foo(self) -> None:
        self.assertTrue(True, "True!")

2. Right-click on test_foo on the source code.
3. Press "Run Test at Cursor"
4. Error occurred.

Extension version: 2025.6.0
VS Code version: Code 1.100.0 (19e0f9e681ecb8e5c09d8784acaa601316ca4571, 2025-05-07T12:48:53.763Z)
OS version: Windows_NT x64 10.0.26100
Modes:
Remote OS version: Linux x64 5.15.167.4-microsoft-standard-WSL2
Remote OS version: Linux x64 5.15.167.4-microsoft-standard-WSL2

• Python version (& distribution if applicable, e.g. Anaconda): 3.13.3
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Global
• Value of the python.languageServer setting: Default

User Settings

languageServer: "Pylance"

testing
• unittestEnabled: true

Installed Extensions

Extension Name	Extension Id	Version
autopep8	ms-	2025.2.0
debugpy	ms-	2025.8.0
js-debug	ms-	1.100.0
python	ms-	2025.6.0
vscode-eslint	dba	3.0.10
vscode-js-profile-table	ms-	1.0.10
vscode-pylance	ms-	2025.4.1

System Info

Item	Value
CPUs	13th Gen Intel(R) Core(TM) i7-13650HX (20 x 2803)
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 skia_graphite: disabled_off video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	undefined
Memory (System)	63.71GB (41.44GB free)
Process Argv	--crash-reporter-id 8dfc9b73-8651-4035-b62d-16aa1889c3ce
Screen Reader	no
VM	0%

Item	Value
Remote	Dev Container: VRM-Addon-for-Blender
OS	Linux x64 5.15.167.4-microsoft-standard-WSL2
CPUs	13th Gen Intel(R) Core(TM) i7-13650HX (20 x 0)
Memory (System)	31.20GB (28.45GB free)
VM	0%

Item	Value
Remote	Dev Container
OS	Linux x64 5.15.167.4-microsoft-standard-WSL2
CPUs	13th Gen Intel(R) Core(TM) i7-13650HX (20 x 0)
Memory (System)	31.20GB (28.45GB free)
VM	0%

A/B Experiments

vsliv368:30146709
vspor879:30202332
vspor708:30202333
vspor363:30204092
vscod805cf:30301675
binariesv615:30325510
c4g48928:30535728
azure-dev_surveyone:30548225
a9j8j154:30646983
962ge761:30959799
h48ei257:31000450
pythontbext0:30879054
cppperfnew:31000557
dwnewjupyter:31046869
pythonrstrctxt:31112756
nativeloc2:31192216
5fd0e150:31155592
dwcopilot:31170013
6074i472:31201624
dwoutputs:31242946
customenabled:31248079
9064b325:31222308
copilot_t_ci:31222730
e5gg6876:31282496
pythoneinst12:31285622
bgtreat:31268568
4gafe986:31271826
31787653:31262186
3e8i5726:31271747
996jf627:31283433
pythonrdcb7:31303018
usemplatestapi:31297334
7bj51361:31289155
747dc170:31275177
g20af354:31278749
pylancecolorcf:31303817
aj953862:31281341
generatesymbolt:31295002
convertfstringf:31295003
gendocf:31295004

[rreuvekamp]

Also affected.

Temporary fix:

pip3 install packaging

in your virtualenv

[quitaiskiluisf]

Also affected.

Temporary fix:

pip3 install packaging

in your virtualenv

Worked for me, but only after I've updated pip itself:

python3 -m pip install --upgrade pip

[pierrebai-adsk]

I'm currently experiencing the same problem, reverting to 2025.4 also fixed it for me.