Use unsigned bytes to back Buffer

[QuLogic]

This makes compressors consistent with v2, and seems more correct than signed bytes.

Fixes #2735

Note that this does not implement accepting both signed and unsigned, as there wasn't a conclusion in #2735 about that.

TODO:

• Add unit tests and/or doctests in docstrings
• Add docstrings and API docs for any new/modified user-facing classes and functions
• New/modified features documented in docs/user-guide/*.rst
• Changes documented in docs/release-notes.rst
• GitHub Actions have all passed
• Test coverage is 100% (Codecov passes)

[QuLogic]

PS, going to ignore tests for now.

[dstansby]

I just fixed uploading code coverage for the GPU tests at #2767, so hopefully when I merge in main here it should improve the patch coverage 🤞

[maxrjones]

Hi @QuLogic and @dstansby, thanks for working on this! Could I help at all with resolving the codecov issue? I'd be super excited to see this completed to enable further trying out imagecodecs with Zarr V3 (e.g., maxrjones/virtual-tiff#4).

[jakirkham]

(clicking update branch in case that fixes it)

[jakirkham]

Closing and reopening to hopefully fix RTD (it has a git checkout error)

[jakirkham]

Ok better RTD checked out the code 😌

[jakirkham]

Looks like Codecov got stuck somewhere. Let's try another close/reopen

[maxrjones]

I don't think that the codecov/patch target will be hit unless the overall coverage actually increases, rather than remains constant. The issue is that two of the lines changed (L87 and L110) are not tested in main either - https://app.codecov.io/gh/zarr-developers/zarr-python/blob/main/src%2Fzarr%2Fcore%2Fbuffer%2Fgpu.py, so the PR isn't decreasing code coverage but still will not hit the 80% target for code coverage for patches (i.e., all new/modified lines of code). Do you prefer to ignore the codecov/patch target or to include unit tests for adding and creating zero length buffers?

[jakirkham]

If someone can add some tests, that would be welcome

What was concerning to me was one Codecov job says "failing after 1s". Though this may be a non-issue and just the report percentage (as you suggested)