Open
Description
Behaviour
When using the Test Explorer with tests written with unittest and those tests are run in a separate process (following an os.fork()), the first test is correctly run and the second one blocks undefinitely.
Steps to reproduce:
Minimal example of Python tests to reproduce the issue:
import unittest
import os
import time
import sys
class ForkedTestCase(unittest.TestCase):
def run(self, result=None):
pid = os.fork()
if pid == 0:
# Mecanics to communicate test results to the main process
# are omitted here
print(">>> run test case")
unittest.TestCase.run(self, result)
print(">>> test case end")
sys.exit(0)
else:
os.waitpid(pid, 0)
class MyTests(ForkedTestCase):
def test_me_please(self):
time.sleep(0.1)
print("Ohhhh yes!")
time.sleep(0.2)
assert True
def test_me_again(self):
time.sleep(0.2)
print("Ohhhh no!")
time.sleep(0.2)
assert False
def test_me_again_and_again(self):
time.sleep(0.3)
print("What ?!")
time.sleep(0.2)
assert True
if __name__ == "__main__":
unittest.main()When launched from a console with e.g. python test.py, tests are correctly run.
But from Test Explorer, a click on the "play" icon of the hole class (MyTests) will result in one test correctly run and others that stay unfinished. Note that individual run of each test works correctly.
Output example:
Received test ids from temp file.
>>> run test case
test_me_again (tests_xx.MyTests) ... Ohhhh no!
FAIL
>>> test case end
>>> run test case
test_me_again_and_again (tests_xx.MyTests) ... What ?!
ok
A ">>> test case end" is missing and the test blocks.
Diagnostic data
Output for Python in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python)
XXX
Extension version: 2025.4.0
VS Code version: Code 1.97.2 (e54c774e0add60467559eb0d1e229c6452cf8447, 2025-02-12T23:20:35.343Z)
OS version: Linux x64 5.15.0-134-generic
Modes:
- Python version (& distribution if applicable, e.g. Anaconda): 3.10.12
- Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Global
- Value of the
python.languageServersetting: Default
User Settings
envFile: "<placeholder>"
languageServer: "Pylance"
testing
• unittestArgs: "<placeholder>"
• unittestEnabled: true
experiments
• optOutFrom: ["pythonDiscoveryUsingWorkers"]
Installed Extensions
| Extension Name | Extension Id | Version |
|---|---|---|
| autodocstring | njp | 0.6.1 |
| black-formatter | ms- | 2025.2.0 |
| cmake | twx | 0.0.17 |
| cmake-tools | ms- | 1.20.53 |
| copilot | Git | 1.277.0 |
| copilot-chat | Git | 0.24.1 |
| cpptools | ms- | 1.24.5 |
| cpptools-extension-pack | ms- | 1.3.1 |
| cpptools-themes | ms- | 2.0.0 |
| debug | web | 0.27.0 |
| debugpy | ms- | 2025.6.0 |
| devdocs | dei | 0.2.0 |
| docker | doc | 0.4.10 |
| edit-with-shell | ryu | 1.3.0 |
| git-graph | mhu | 1.30.0 |
| gitblame | wad | 11.1.2 |
| gitlab-workflow | Git | 6.11.0 |
| go | gol | 0.46.1 |
| hexeditor | ms- | 1.11.1 |
| jenkinsfile-support | sec | 0.1.0 |
| js-debug | ms- | 1.97.1 |
| js-debug-companion | ms- | 1.1.3 |
| json | Zai | 2.0.2 |
| lldb-vscode | lan | 0.2.3 |
| magit | kah | 0.6.66 |
| markdown-all-in-one | yzh | 3.6.3 |
| org-mode | too | 0.5.0 |
| python | ms- | 2025.4.0 |
| remote-containers | ms- | 0.401.0 |
| remote-explorer | ms- | 0.4.3 |
| remote-server | ms- | 1.5.2 |
| remote-ssh | ms- | 0.119.0 |
| remote-ssh-edit | ms- | 0.87.0 |
| remote-wsl | ms- | 0.88.5 |
| rest-client | hum | 0.25.1 |
| rewrap | stk | 1.16.3 |
| rust-analyzer | rus | 0.3.2433 |
| swiper | wen | 2.1.2 |
| test-adapter-converter | ms- | 0.2.1 |
| vscode-docker | ms- | 1.29.5 |
| vscode-groovy-lint | Nic | 3.3.1 |
| vscode-highlight | fab | 1.9.0 |
| vscode-js-profile-table | ms- | 1.0.10 |
| vscode-kubernetes-tools | ms- | 1.3.20 |
| vscode-lldb | vad | 1.11.4 |
| vscode-pylance | ms- | 2025.4.1 |
| vscode-remote-extensionpack | ms- | 0.26.0 |
| vscode-test-explorer | hbe | 2.22.1 |
| vscode-yaml | red | 1.17.0 |
System Info
| Item | Value |
|---|---|
| CPUs | Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz (8 x 2812) |
| 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: disabled_software vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: disabled_off webnn: disabled_off |
| Load (avg) | 4, 3, 3 |
| Memory (System) | 31.11GB (10.31GB free) |
| Process Argv | . --crash-reporter-id e924368d-d11e-4156-ab9c-783e009058c9 |
| Screen Reader | no |
| VM | 3% |
| DESKTOP_SESSION | cinnamon |
| XDG_CURRENT_DESKTOP | X-Cinnamon |
| XDG_SESSION_DESKTOP | cinnamon |
| XDG_SESSION_TYPE | x11 |
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dwcopilot:31170013
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dwoutputs:31242946
customenabled:31248079
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