Test workflow for WoA

[pdeep854]

Adds a test workflow to enable validation on WoA. This ensures PyTorch-related logic and dependencies are exercised in a WoA environment, improving coverage and catching platform-specific issues early

[matthewdouglas]

Hi @pdeep854

Last week I started a branch to add this to the test CI here: https://github.com/bitsandbytes-foundation/bitsandbytes/tree/windows-arm64-cpu-ci

I started with just the nightly rather than PR workflow, as typically our Windows tests are quite a bit slower than Linux or macOS. I did notice that the tests are even slower than I would have expected though. See a run here:
https://github.com/bitsandbytes-foundation/bitsandbytes/actions/runs/26659204158/job/78577334602

Secondly I notice your comment Windows ARM64 minimum torch version is 2.12.0 but the tests did pass on torch 2.7.1.

I have a few thoughts on some potential improvement that I'm wanting to try out. I'll follow up on that soon. Thanks!

[pdeep854]

Hi @matthewdouglas
Yes it will work for pytorch >=2.7. I used the latest release to avoid any compatibility issues.

[matthewdouglas]

Gotcha. I realized I made a mistake here and was building on x86-64 machine, to run tests on the ARM runner, emulated. So rerunning it now!

[github-actions]

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[matthewdouglas]

This looks good so I'll merge. I will follow up with separate PRs for nightly tests and a couple of other improvements. Thanks!