pytest test discovery does not run

[cdeil]

Type: Bug

Summary

Pytest gutter icons (play buttons) are missing after VS Code starts. Test discovery does not run automatically even though python.testing.pytestEnabled is true.

Workaround: Running Test: Refresh Tests from Command Palette fixes the issue until VS Code restarts.

Steps to Reproduce

1. Open a Python project with pytest configured
2. Ensure .vscode/settings.json has:

   {
     "python.testing.pytestArgs": ["tests"],
     "python.testing.unittestEnabled": false,
     "python.testing.pytestEnabled": true
   }

3. Close and restart VS Code
4. Open a test file (e.g., test_stock.py)
5. Expected: Green play button icons appear next to test functions
6. Actual: No gutter icons, Test Explorer is empty

Workaround

Run Test: Refresh Tests from Command Palette → Icons appear and tests work.

Note: Developer: Reload Window does NOT fix the issue.

Environment

• VS Code: 1.108.2
• OS: macOS arm64 (Darwin 25.2.0)
• Python: 3.14.0
• pytest: 9.0.2
• ms-python.python: 2026.0.0

Log Evidence

Python.log shows no test discovery on startup:

[info] Active interpreter: .venv/bin/python
[info] Starting Pylance language server.
[error] Unable to find workspace for given file

After running Test: Refresh Tests, the log shows:

[info] Environment variables set for pytest discovery: PYTHONPATH=...
[info] Started pytest discovery subprocess for workspace ...
[info] Pytest discovery completed

Additional Context

• Single window scenario (not multi-window)
• pytest works fine from terminal: python -m pytest --collect-only succeeds
• Python environment is correctly detected

Extension version: 2026.0.0
VS Code version: Code 1.108.2 (Universal) (c9d77990917f3102ada88be140d28b038d1dd7c7, 2026-01-21T13:52:09.270Z)
OS version: Darwin arm64 25.2.0
Modes:

System Info

Item	Value
CPUs	Apple M3 (8 x 2400)
GPU Status	2d_canvas: enabled 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 trees_in_viz: disabled_off video_decode: enabled video_encode: enabled webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	2, 2, 2
Memory (System)	16.00GB (0.11GB free)
Process Argv	--crash-reporter-id ea819cd1-e9b8-4654-b394-6ba9979e300c
Screen Reader	no
VM	0%

A/B Experiments

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nativeloc1:31344060
dwcopilot:31170013
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copilot_t_ci:31333650
e5gg6876:31282496
pythonrdcb7:31342333
6518g693:31436602
aj953862:31281341
6abeh943:31336334
envsdeactivate2:31353495
cloudbuttont:31379625
42190218_ostrepl:31403339
use-responses-api:31390855
je187915:31401257
ec5jj548:31422691
cmp-ext-treat:31426748
cp_cls_c_966_ss:31446431
c0683394:31419495
ge8j1254_inline_auto_hint_haiku:31431912
nes-autoexp-10:31446583
a5gib710:31434435
5j92g670_sonnet:31446810
rename_enabled:31436409
7a04d226_do_not_restore_last_panel_session:31438103
anthropic_thinking_t:31432745
h0hdh950:31428394
cp_cls_t_1081:31443828
copilot-nes-oct-trt:31432596
ia-use-proxy-models-svc:31450090
nes-jump-on-with-edit:31450417
nes-slash-models-on:31441832
core-renderer-profiling-on:31440367
nes-set-to-on:31441941
a43f0574a:31442826
ts_provider_disabled:31446105
c0ci8992_validated:31449878
nes-conv-2-3:31447852

[cdeil]

This screenshot shows the issue (no "play" button for tests because pytest discovery didn't run).

I do have a setup where I have a second frontend repo checked out in a sub-folder (and in .gitignore or the main Python backend repo). This is with uv as package manager and using also the ruff extension in VS Code.

There are two errors about not being able to find the workspace for given file in the Python extension log:

2026-01-23 14:30:47.963 [error] Unable to find workspace for given file
2026-01-23 14:30:51.984 [error] Unable to find workspace for given file

But I don't know what the files are and if it's related to the pytest issue. The error does not appear when I open more test files.

Overall it looks like a bug or race condition in refreshSingleWorkspace or other workspace-activation related functions in the case where there are two repos involved.