Cannot run unittest in parallel anymore

[NicolasM-Forsk]

Type: Bug

A few weeks/months ago, I was able to run unittests in parallel by selecting many of them and clicking on "run".
This doesn't work anymore, tests are run sequencially which takes much more time.
Did you change the internal mechanism?

Extension version: 2025.0.0
VS Code version: Code 1.97.2 (e54c774e0add60467559eb0d1e229c6452cf8447, 2025-02-12T23:20:35.343Z)
OS version: Windows_NT x64 10.0.22621
Modes:
Remote OS version: Linux x64 5.15.90.1-microsoft-standard-WSL2
Remote OS version: Linux x64 5.15.90.1-microsoft-standard-WSL2

• Python version (& distribution if applicable, e.g. Anaconda): 3.11.10
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Venv
• Value of the python.languageServer setting: Default

User Settings

envFile: "<placeholder>"

languageServer: "Pylance"

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

Installed Extensions

Extension Name	Extension Id	Version
autopep8	ms-	2024.1.11501016
cmake	twx	0.0.17
cmake-tools	ms-	1.19.52
cpptools	ms-	1.23.6
cpptools-extension-pack	ms-	1.3.0
csdevkit	ms-	1.16.6
csharp	ms-	2.63.32
debugpy	ms-	2025.0.1
even-better-toml	tam	0.21.2
flake8	ms-	2024.0.0
git-graph	mhu	1.30.0
gitlens	eam	16.3.0
js-debug	ms-	1.97.1
jupyter	ms-	2025.1.0
jupyter-renderers	ms-	1.1.0
paste-as-string-array	sha	1.0.0
python	ms-	2025.0.0
spectral	sto	1.1.4
typespec-vscode	typ	0.65.0
vscode-catch2-test-adapter	mat	4.12.2
vscode-docker	ms-	1.29.4
vscode-dotnet-runtime	ms-	2.2.8
vscode-js-profile-table	ms-	1.0.10
vscode-jupyter-cell-tags	ms-	0.1.9
vscode-jupyter-slideshow	ms-	0.1.6
vscode-language-pack-fr	MS-	1.97.2025021209
vscode-openapi	42C	4.31.0
vscode-pylance	ms-	2025.2.1
vscode-sort-json	ric	1.20.0
vscode-xml	red	0.27.2
vscode-yaml	red	1.16.0
vscode-yaml-sort	Pas	6.6.1

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-10700 CPU @ 2.90GHz (16 x 2904)
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)	31.72GB (4.47GB free)
Process Argv
Screen Reader	no
VM	0%

Item	Value
Remote	WSL: Ubuntu-22.04
OS	Linux x64 5.15.90.1-microsoft-standard-WSL2
CPUs	Intel(R) Core(TM) i7-10700 CPU @ 2.90GHz (16 x 0)
Memory (System)	11.68GB (3.94GB free)
VM	0%

Item	Value
Remote	WSL: Ubuntu-22.04
OS	Linux x64 5.15.90.1-microsoft-standard-WSL2
CPUs	Intel(R) Core(TM) i7-10700 CPU @ 2.90GHz (16 x 0)
Memory (System)	11.68GB (3.94GB free)
VM	0%

[lukaskoehrer]

I have a similar issue since upgrading to 2025.0.0. If i click on "run" for a certain test while some other tests are running they are not added to the current test run and "Test Results" only shows "Finished running tests!". While the first test runs through, the second test does not seem to be started.

When reverting to 2024.22.2 I can run tests in parallel again.

I also could not figure out if this change is intended or not, or how to restore the old behavior on the new version.

[nmoreaud]

I have a similar issue since upgrading to 2025.0.0. If i click on "run" for a certain test while some other tests are running they are not added to the current test run and "Test Results" only shows "Finished running tests!". While the first test runs through, the second test does not seem to be started.

When reverting to 2024.22.2 I can run tests in parallel again.

I also could not figure out if this change is intended or not, or how to restore the old behavior on the new version.

Yes, same here.

[eleanorjboyd]

Hi! Intended behavior is being able to run them in parallel. Can you set your log levels to debug and send them here? To do so set developer: set long level in the command prompt and then look in the python output channel

[nmoreaud]

Here is a sample workspace: seq_tests.zip
I reproduce the two behaviors previously mentioned.
Please note that there are both code_workspace and .vscode/launch.json, to ensure that "justMyCode" is taken into account across versions of VSCode (it is often broken after updates for workspaces).

[eleanorjboyd]

Hi! What if you install pytest-xdist and then add the argument -n auto. This is what supports running tests in parallel, that specific plugin

[lukaskoehrer]

I am running my tests with pytest and pytest-xdist and the argument -n auto.

While vscode correctly starts up multiple workers and runs the tests in parallel if I click on a group of tests, starting another group or another single test via clicking on it does not work anymore if the run initiated via the first click has not finished yet.

[nmoreaud]

In previous versions, I didn't need pytest-xdist. In latest version pytest-xdist works fine, except that we have lost in interactivity.
As @lukaskoehrer says, we cannot start tests incrementally, we must wait for one test session to finish before running a new one.