Run tests in parallel via tox for 3.5x speedup by hugovk · Pull Request #9516 · python-pillow/Pillow · GitHub

#9342 isn't ready to enable pytest-xdist across the board (CI and local) because of difficulties with leak tests.

But let's at least have the benefits for local testing via tox, if not in CI (which doesn't use tox).

Also add the test-arrow extra to enable some more tests.

pytest times on macOS with tox -e py314 on cached build:

Old table with test-arrow

	No test-arrow	With test-arrow
Sequential	41.23s	42.41s
Parallel	11.71s	13.39s
Speedup	3.52x	3.17x

	Time
Sequential	41.23s
Parallel	11.71s
Speedup	3.52x

Edit: removed the test-arrow extra because it fails on 3.15 due to missing wheel.

Why wouldn't the leak failure happen locally?

That's a good question! It'd be easier to investigate if it did happen locally :)

I just tried 10 runs of tox -e py314 and hit the spider KeyError we also had at #9342 (comment):

    def teardown_module() -> None:
>       del Image.EXTENSION[".spider"]
            ^^^^^^^^^^^^^^^^^^^^^^^^^^
E       KeyError: '.spider'

So I've re-added that fix and 10 runs passed, followed by 10 x tox -e py310 that passed.

This PR contains the following updates: | Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) | |---|---|---|---| | [pillow](https://github.com/python-pillow/Pillow) ([changelog](https://github.com/python-pillow/Pillow/releases)) | `<12.1.2,>=12.1.1` → `<12.2.1,>=12.2.0` | ![age](https://developer.mend.io/api/mc/badges/age/pypi/pillow/12.2.0?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/pillow/12.1.1/12.2.0?slim=true) | --- ### Release Notes <details> <summary>python-pillow/Pillow (pillow)</summary> ### [`v12.2.0`](https://github.com/python-pillow/Pillow/releases/tag/12.2.0) [Compare Source](python-pillow/Pillow@12.1.1...12.2.0) <https://pillow.readthedocs.io/en/stable/releasenotes/12.2.0.html> #### Documentation - Update 12.2.0 release notes [#9522](python-pillow/Pillow#9522) \[[@hugovk](https://github.com/hugovk)] - Add loader plugins: AMOS abk, Atari Degas, 40+ more obscure formats via Netpbm [#9482](python-pillow/Pillow#9482) \[[@bitplane](https://github.com/bitplane)] - Update Python versions [#9515](python-pillow/Pillow#9515) \[[@radarhere](https://github.com/radarhere)] - Jeffrey A. Clark -> Jeffrey 'Alex' Clark [#9513](python-pillow/Pillow#9513) \[[@aclark4life](https://github.com/aclark4life)] - Add release notes for [#9394](python-pillow/Pillow#9394), [#9419](python-pillow/Pillow#9419) and [#9456](python-pillow/Pillow#9456) [#9467](python-pillow/Pillow#9467) \[[@radarhere](https://github.com/radarhere)] - Add Amiga Workbench .info loader to 3rd party plugins list [#9459](python-pillow/Pillow#9459) \[[@bitplane](https://github.com/bitplane)] - Merge PFM documentation into PPM [#9434](python-pillow/Pillow#9434) \[[@radarhere](https://github.com/radarhere)] - Update macOS tested Pillow versions [#9431](python-pillow/Pillow#9431) \[[@radarhere](https://github.com/radarhere)] - Fix CVE number [#9430](python-pillow/Pillow#9430) \[[@hugovk](https://github.com/hugovk)] #### Dependencies - Update xz to 5.8.3 [#9523](python-pillow/Pillow#9523) \[[@radarhere](https://github.com/radarhere)] - Update libjpeg-turbo to 3.1.4.1 [#9507](python-pillow/Pillow#9507) \[[@radarhere](https://github.com/radarhere)] - Update libpng to 1.6.56 [#9499](python-pillow/Pillow#9499) \[[@radarhere](https://github.com/radarhere)] - Update freetype to 2.14.3 [#9485](python-pillow/Pillow#9485) \[[@radarhere](https://github.com/radarhere)] - Updated libavif to 1.4.1 [#9479](python-pillow/Pillow#9479) \[[@radarhere](https://github.com/radarhere)] - Updated harfbuzz to 13.2.1 [#9461](python-pillow/Pillow#9461) \[[@radarhere](https://github.com/radarhere)] - Update Ghostscript to 10.7.0 [#9469](python-pillow/Pillow#9469) \[[@radarhere](https://github.com/radarhere)] - Update harfbuzz to 13.0.1 [#9453](python-pillow/Pillow#9453) \[[@radarhere](https://github.com/radarhere)] - Update libavif to 1.4.0 [#9460](python-pillow/Pillow#9460) \[[@radarhere](https://github.com/radarhere)] - Update freetype to 2.14.2 [#9449](python-pillow/Pillow#9449) \[[@radarhere](https://github.com/radarhere)] - Update actions/download-artifact action to v8 [#9451](python-pillow/Pillow#9451) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Updated libpng to 1.6.55 [#9425](python-pillow/Pillow#9425) \[[@radarhere](https://github.com/radarhere)] #### Testing - Cleanup .spider extension in the same test where it is added [#9517](python-pillow/Pillow#9517) \[[@radarhere](https://github.com/radarhere)] - Run tests in parallel via tox for 3.5x speedup [#9516](python-pillow/Pillow#9516) \[[@hugovk](https://github.com/hugovk)] - Enable colour in CI logs [#9486](python-pillow/Pillow#9486) \[[@hugovk](https://github.com/hugovk)] - Update Ghostscript to 10.7.0 [#9469](python-pillow/Pillow#9469) \[[@radarhere](https://github.com/radarhere)] - Simplify TGA test code [#9477](python-pillow/Pillow#9477) \[[@radarhere](https://github.com/radarhere)] - Update tests to check for ValueError when encoding an empty image [#9464](python-pillow/Pillow#9464) \[[@radarhere](https://github.com/radarhere)] - Upgrade CI from `macos-15-intel` to `macos-26-intel` [#9454](python-pillow/Pillow#9454) \[[@hugovk](https://github.com/hugovk)] - Add check-case-conflict hook [#9446](python-pillow/Pillow#9446) \[[@radarhere](https://github.com/radarhere)] - Specify platform when pulling docker image [#9440](python-pillow/Pillow#9440) \[[@radarhere](https://github.com/radarhere)] - GHA: Cache libavif and webp builds for Ubuntu [#9437](python-pillow/Pillow#9437) \[[@hugovk](https://github.com/hugovk)] - Update macOS tested Pillow versions [#9431](python-pillow/Pillow#9431) \[[@radarhere](https://github.com/radarhere)] #### Other changes - Check calloc return value [#9527](python-pillow/Pillow#9527) \[[@radarhere](https://github.com/radarhere)] - Check all allocs in the Arrow tree [#9488](python-pillow/Pillow#9488) \[[@wiredfool](https://github.com/wiredfool)] - Reject non-numeric elements inside list coords [#9526](python-pillow/Pillow#9526) \[[@hugovk](https://github.com/hugovk)] - Move variable declaration inside define [#9525](python-pillow/Pillow#9525) \[[@radarhere](https://github.com/radarhere)] - Resize tall images vertically first [#9524](python-pillow/Pillow#9524) \[[@radarhere](https://github.com/radarhere)] - Avoid overflow by not adding extents together [#9520](python-pillow/Pillow#9520) \[[@hugovk](https://github.com/hugovk)] - Use long for glyph position [#9518](python-pillow/Pillow#9518) \[[@hugovk](https://github.com/hugovk)] - Raise an error if the trailer chain loops back on itself [#9519](python-pillow/Pillow#9519) \[[@hugovk](https://github.com/hugovk)] - Only read as much data from gzip-decompressed data as necessary [#9521](python-pillow/Pillow#9521) \[[@hugovk](https://github.com/hugovk)] - Allow None extents in C setimage() [#9504](python-pillow/Pillow#9504) \[[@radarhere](https://github.com/radarhere)] - Use critical sections to protect FontObject [#9498](python-pillow/Pillow#9498) \[[@colesbury](https://github.com/colesbury)] - Add ImageText.Text.wrap() to wrap text [#9286](python-pillow/Pillow#9286) \[[@radarhere](https://github.com/radarhere)] - Always call StubHandler open() when opening StubImageFile [#9412](python-pillow/Pillow#9412) \[[@radarhere](https://github.com/radarhere)] - Improved BCn overflow check [#9043](python-pillow/Pillow#9043) \[[@radarhere](https://github.com/radarhere)] - Image will never be None [#9512](python-pillow/Pillow#9512) \[[@radarhere](https://github.com/radarhere)] - Raise EOFError when seeking too far in PSD [#9388](python-pillow/Pillow#9388) \[[@radarhere](https://github.com/radarhere)] - Raise error if ImageGrab subprocess gives non-zero returncode [#9321](python-pillow/Pillow#9321) \[[@radarhere](https://github.com/radarhere)] - Allow for different palette entry sizes when correcting BMP pixel data offset [#9472](python-pillow/Pillow#9472) \[[@radarhere](https://github.com/radarhere)] - Ignore unspecified extra samples for TIFF separate planar configuration [#9514](python-pillow/Pillow#9514) \[[@radarhere](https://github.com/radarhere)] - Add PERF to lint and fix findings [#9510](python-pillow/Pillow#9510) \[[@hugovk](https://github.com/hugovk)] - Switch iOS back to macos-15-intel [#9509](python-pillow/Pillow#9509) \[[@radarhere](https://github.com/radarhere)] - Catch struct.error [#9505](python-pillow/Pillow#9505) \[[@radarhere](https://github.com/radarhere)] - Check PyCapsule\_GetPointer and PyBytes\_FromStringAndSize return values [#9508](python-pillow/Pillow#9508) \[[@radarhere](https://github.com/radarhere)] - Fix missing null dereference checks [#9489](python-pillow/Pillow#9489) \[[@wiredfool](https://github.com/wiredfool)] - CI: Retry failed downloads [#9506](python-pillow/Pillow#9506) \[[@hugovk](https://github.com/hugovk)] - Use PyModule\_AddObjectRef [#9503](python-pillow/Pillow#9503) \[[@radarhere](https://github.com/radarhere)] - Release reference to encoder on error [#9500](python-pillow/Pillow#9500) \[[@radarhere](https://github.com/radarhere)] - Fixed AVIF and WEBP dealloc [#9501](python-pillow/Pillow#9501) \[[@radarhere](https://github.com/radarhere)] - Check PyType\_Ready return values [#9502](python-pillow/Pillow#9502) \[[@radarhere](https://github.com/radarhere)] - Check if PyObject\_CallMethod result is NULL [#9494](python-pillow/Pillow#9494) \[[@radarhere](https://github.com/radarhere)] - Do not use palette from grayscale or bilevel colorspace when reading JPEG2000 images [#9468](python-pillow/Pillow#9468) \[[@radarhere](https://github.com/radarhere)] - If TGA v2 extension area specifies no alpha, fill alpha channel [#9478](python-pillow/Pillow#9478) \[[@radarhere](https://github.com/radarhere)] - Set image pixels individually on 32-bit Windows [#9492](python-pillow/Pillow#9492) \[[@radarhere](https://github.com/radarhere)] - Add error messages before returning NULL when encoding [#9493](python-pillow/Pillow#9493) \[[@radarhere](https://github.com/radarhere)] - Fix `_getxy` refcount leaks [#9487](python-pillow/Pillow#9487) \[[@hugovk](https://github.com/hugovk)] - Fix invalid test font [#9483](python-pillow/Pillow#9483) \[[@radarhere](https://github.com/radarhere)] - Add Exif tag "FrameRate" [#9470](python-pillow/Pillow#9470) \[[@zhiyuanouyang](https://github.com/zhiyuanouyang)] - Support reading JPEG2000 images with CMYK palettes [#9456](python-pillow/Pillow#9456) \[[@radarhere](https://github.com/radarhere)] - Simplify `setimage()` by always passing extents [#9395](python-pillow/Pillow#9395) \[[@radarhere](https://github.com/radarhere)] - If bitmap buffer is empty, do not render anything [#8324](python-pillow/Pillow#8324) \[[@radarhere](https://github.com/radarhere)] - Change to ValueError when encoding an empty image [#9394](python-pillow/Pillow#9394) \[[@radarhere](https://github.com/radarhere)] - Add FontFile.to\_imagefont() [#9419](python-pillow/Pillow#9419) \[[@fjhenigman](https://github.com/fjhenigman)] - \[pre-commit.ci] pre-commit autoupdate [#9450](python-pillow/Pillow#9450) \[@[pre-commit-ci\[bot\]](https://github.com/apps/pre-commit-ci)] - Use walrus operator [#9448](python-pillow/Pillow#9448) \[[@radarhere](https://github.com/radarhere)] - Only close file handle in ImagePalette.save() if it was opened internally [#9444](python-pillow/Pillow#9444) \[[@bysiber](https://github.com/bysiber)] - Fix `self.decode` typo [#9445](python-pillow/Pillow#9445) \[[@bysiber](https://github.com/bysiber)] - Fix BMP RLE delta escape reading from wrong file position [#9443](python-pillow/Pillow#9443) \[[@bysiber](https://github.com/bysiber)] - Correct error check when encoding AVIF images [#9442](python-pillow/Pillow#9442) \[[@radarhere](https://github.com/radarhere)] - Fix unexpected error when saving zero dimension images [#9391](python-pillow/Pillow#9391) \[[@radarhere](https://github.com/radarhere)] - Use uppercase format ID for PALM [#9435](python-pillow/Pillow#9435) \[[@radarhere](https://github.com/radarhere)] </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR is behind base branch, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Reviewed-on: https://git.tainton.uk/repos/webexmemebot/pulls/579 Reviewed-by: Luke Tainton <luke@tainton.uk> Co-authored-by: renovate[bot] <renovate-bot@git.tainton.uk> Co-committed-by: renovate[bot] <renovate-bot@git.tainton.uk>

hugovk added the Testing label Mar 30, 2026

hugovk force-pushed the tox-pytest-xdist branch 2 times, most recently from 5c1b1d1 to b45a17a Compare March 30, 2026 13:23

hugovk changed the title Run tests in parallel via tox for 3x speedup Run tests in parallel via tox for 3.5x speedup Mar 30, 2026

Run tests in parallel via tox

f80de21

hugovk force-pushed the tox-pytest-xdist branch from b45a17a to f80de21 Compare March 30, 2026 13:41

Safer test_file_spider teardown under pytest-xdist

228a85e

radarhere merged commit 1f74a55 into python-pillow:main Mar 31, 2026
56 checks passed

hugovk deleted the tox-pytest-xdist branch March 31, 2026 11:18

Run tests in parallel via tox for 3.5x speedup by hugovk · Pull Request #9516 · python-pillow/Pillow · GitHub

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Run tests in parallel via tox for 3.5x speedup - #9516

Run tests in parallel via tox for 3.5x speedup#9516
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Run tests in parallel via tox for 3.5x speedup by hugovk · Pull Request #9516 · python-pillow/Pillow · GitHub

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Run tests in parallel via tox for 3.5x speedup - #9516

Run tests in parallel via tox for 3.5x speedup#9516radarhere merged 2 commits intopython-pillow:mainpython-pillow/Pillow:mainfrom hugovk:tox-pytest-xdisthugovk/Pillow:tox-pytest-xdistCopy head branch name to clipboard

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Run tests in parallel via tox for 3.5x speedup#9516
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