Debugging unittests sometimes opens new tab for each step #25545
Description
Type: Bug
Behaviour
When debugging an unittest, stepping through the lines result in a new tab being opened with each step. This is intermittent and may be resolved when closing and reopening vscode.
I've noticed the tabs opened in this way do not display their path hierarchy below the tab name as most tabs do.
Thank you!
Steps to reproduce:
- I've encountered this a few times, but not sure exactly under what circumstances it happens
- Debug an unittest by alt clicking the "run test" icon in the gutter
- Step through, or into any part of the code
- The debugger will advance to the next step, and open a new tab with the file that corresponds to that step.
Diagnostic data
Output for Python in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python)
2025-10-24 07:21:26.726 [info] Running UNITTEST execution for the following test ids: test_perforce_admin_utils.TestPerforceAdminUtilsNotDry.test_create_client
2025-10-24 07:21:26.727 [info] Attempting to use temp directory for test ids file, file name: test-ids-260d7978605ae195db9a.txt
2025-10-24 07:21:26.729 [info] All environment variables set for unittest execution, PYTHONPATH: "d:\\local_dev\\depot_creation\\src"
2025-10-24 07:21:26.862 [info] > Y:/irenec/dev/pipelaunch/venv/Scripts/activate.bat && echo 'e8b39361-0157-4923-80e1-22d70d46dee6' && python ~/.vscode/extensions/ms-python.python-2025.16.0-win32-x64/python_files/printEnvVariables.py
2025-10-24 07:21:26.862 [info] shell: commandPrompt
2025-10-24 07:21:27.149 [info] Discover tests for workspace name: depot creation repo - uri: d:\local_dev\depot_creation\src\src\depot_creation\tests\test_depot_creator.py
2025-10-24 07:21:27.150 [info] Discovering unittest tests for workspace d:\local_dev\depot_creation\src with arguments: c:\Users\irenec\.vscode\extensions\ms-python.python-2025.16.0-win32-x64\python_files\unittestadapter\discovery.py,--udiscovery,-v,-s,d:/local_dev/depot_creation/src/src/depot_creation/tests,-p,test_*.py
2025-10-24 07:21:27.165 [info] > Y:/irenec/dev/pipelaunch/venv/Scripts/activate.bat && echo 'e8b39361-0157-4923-80e1-22d70d46dee6' && python ~/.vscode/extensions/ms-python.python-2025.16.0-win32-x64/python_files/printEnvVariables.py
2025-10-24 07:21:27.165 [info] shell: commandPrompt
2025-10-24 07:21:27.459 [info] Running DEBUG unittest for workspace d:\local_dev\depot_creation\src with arguments: c:\Users\irenec\.vscode\extensions\ms-python.python-2025.16.0-win32-x64\python_files\unittestadapter\execution.py,--udiscovery,-v,-s,d:/local_dev/depot_creation/src/src/depot_creation/tests,-p,test_*.py
2025-10-24 07:21:27.459 [info] Using configuration in workspace
2025-10-24 07:21:27.709 [info] > Y:\irenec\dev\pipelaunch\venv\Scripts\python.exe ~\.vscode\extensions\ms-python.python-2025.16.0-win32-x64\python_files\unittestadapter\discovery.py --udiscovery -v -s d:/local_dev/depot_creation/src/src/depot_creation/tests -p test_*.py
2025-10-24 07:21:27.709 [info] cwd: d:\local_dev\depot_creation\src
2025-10-24 07:21:50.405 [info] Test Result named pipe \\.\pipe\python-test-results-5d0efa09c560c8b1c64d cancelled
Extension version: 2025.16.0
VS Code version: Code 1.105.1 (7d842fb85a0275a4a8e4d7e040d2625abbf7f084, 2025-10-14T22:33:36.618Z)
OS version: Windows_NT x64 10.0.26100
Modes:
- Python version (& distribution if applicable, e.g. Anaconda): 3.9.13
- Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Venv
- Value of the
python.languageServersetting: Default
User Settings
Multiroot scenario, following user settings may not apply:
languageServer: "Pylance"
testing
• debugPort: 2000
• unittestArgs: "<placeholder>"
• unittestEnabled: true
• autoTestDiscoverOnSavePattern: "<placeholder>"
Installed Extensions
| Extension Name | Extension Id | Version |
|---|---|---|
| auto-comment-blocks | kev | 1.0.1 |
| autodocstring | njp | 0.6.1 |
| copilot | Git | 1.387.0 |
| copilot-chat | Git | 0.32.3 |
| debugpy | ms- | 2025.14.1 |
| extendscript-debug | Ado | 2.1.0 |
| gitlens | eam | 17.6.2 |
| js-debug | ms- | 1.105.0 |
| js-debug-companion | ms- | 1.1.3 |
| python | ms- | 2025.16.0 |
| vscode-js-profile-table | ms- | 1.0.10 |
| vscode-pull-request-github | Git | 0.120.1 |
| vscode-pylance | ms- | 2025.8.3 |
| vscode-python-envs | ms- | 1.10.0 |
System Info
| Item | Value |
|---|---|
| CPUs | Intel(R) Xeon(R) W-2225 CPU @ 4.10GHz (8 x 4104) |
| 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 vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off |
| Load (avg) | undefined |
| Memory (System) | 63.69GB (41.30GB free) |
| Process Argv | Y:\irenec\vscode\irenec_pipelaunch20.code-workspace --crash-reporter-id 0f3862e7-250e-488d-8961-f1c20f56d1d7 |
| Screen Reader | no |
| VM | 0% |
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