Tests starting with an Umlaut aren't registered by the testing environment

[RealTachyon]

Type: Bug

Behaviour

When trying to use the testing panel, test files starting with an Umlaut (ÄÖÜ) fail to be located.

Steps to Reproduce:

Write out the test files

Write out the following code in two separate files, both of which need to be placed in your testing folder.
The first one is named ether_tests.py.
The second one is named äther_tests.py.

import unittest

class Something(unittest.TestCase):
	def test_1(self) -> None:
		pass

Enable pytests in settings

Make sure that your settings.json has the pytests enabled

"python.testing.unittestArgs": [
	"-v",
	"-s",
	"./tests",
	"-p",
	"*test*.py"
],
"python.testing.pytestEnabled": false,
"python.testing.unittestEnabled": true,

Load in the tests

1. Go to the testing panel
2. Press Refresh Tests

Expected behavior:

Both ether_tests.py and äther_tests.py should show up.

Problematic behavior:

Only ether_tests.py shows up.

Extension version: 2025.4.0
VS Code version: Code 1.99.3 (17baf841131aa23349f217ca7c570c76ee87b957, 2025-04-15T23:18:46.076Z)
OS version: Windows_NT x64 10.0.19045
Modes:

• Python version (& distribution if applicable, e.g. Anaconda): 3.13.1
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Venv
• Value of the python.languageServer setting: Default

User Settings

languageServer: "Pylance"

testing
• unittestArgs: "<placeholder>"
• unittestEnabled: true

Installed Extensions

Extension Name	Extension Id	Version
autodocstring	njp	0.6.1
better-comments	aar	3.0.2
black-formatter	ms-	2025.2.0
blender-development	Jac	0.0.25
blender-development-experimental-fork	CGP	0.0.183
calculate	aca	2.1.0
code-runner	for	0.12.2
code-spell-checker	str	4.0.47
code-spell-checker-german	str	2.3.3
cpptools	ms-	1.24.5
datawrangler	ms-	1.20.1
debugpy	ms-	2025.6.0
docxreader	Sha	1.1.3
emlviewer	joe	0.0.4
even-better-toml	tam	0.21.2
extension-test-runner	ms-	0.0.12
folder-color	Ser	1.0.1
folder-path-color-auto	jjh	0.0.2
git-graph	mhu	1.30.0
html-md-converter	and	0.0.8
html-preview-vscode	geo	0.2.5
identification	und	0.0.1
indent-rainbow	ode	8.3.1
isort	ms-	2025.0.0
js-debug	ms-	1.97.1
js-debug-companion	ms-	1.1.3
json	Zai	2.0.2
jupyter	ms-	2025.3.0
languagetool	ray	1.0.1
latex-workshop	Jam	10.9.0
live-server	ms-	0.4.15
make-hidden	dev	4.0.4
markdown-all-in-one	yzh	3.6.3
markdown-wysiwyg	ada	0.7.10
multi-command	ryu	1.6.0
output-colorizer	IBM	0.1.2
powershell	ms-	2025.0.0
python	ms-	2025.4.0
python-docstring-highlighter	rod	0.2.4
python-init-generator	See	0.0.15
quick-python-print	Wei	0.3.1
rainbow-bracket	tal	1.0.2
rainbow-csv	mec	3.19.0
search-folders	ym-	0.0.1
seito-openfile	Fr4	2.2.4
selected-lines-count	gur	1.4.0
test-adapter-converter	ms-	0.2.1
vscjsontableeditor	Alt	0.10.0
vscode-ansi	ili	1.1.7
vscode-autohotkey-debug	zer	1.11.1
vscode-autohotkey-plus-plus	mar	6.7.0
vscode-designer-addon	nod	1.1.18
vscode-edit-csv	jan	0.11.3
vscode-eslint	dba	3.0.10
vscode-icons	vsc	12.12.0
vscode-js-profile-table	ms-	1.0.10
vscode-jupyter-cell-tags	ms-	0.1.9
vscode-jupyter-slideshow	ms-	0.1.6
vscode-markdown-preview-include	sta	0.0.4
vscode-mermaid-editor	tom	0.19.1
vscode-peacock	joh	4.2.2
vscode-pylance	ms-	2025.4.1
vscode-python-test-adapter	lit	0.8.2
vscode-python-timeit	Has	1.3.8
vscode-remove-final-newlines	DoC	1.2.0
vscode-sort	hen	0.2.5
vscode-sqlite3-editor	yy0	1.0.205
vscode-subword-navigation	ow	1.2.0
vscode-test-explorer	hbe	2.22.1
wordcounter	kir	2.4.4

System Info

Item	Value
CPUs	AMD Ryzen Threadripper 2970WX 24-Core Processor (48 x 2994)
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)	95.88GB (50.83GB free)
Process Argv	--crash-reporter-id 0f924fbb-88c9-44bf-bd09-f8e30396fdf9
Screen Reader	no
VM	0%

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