Test pint versions

[lewisjared]

Description

Checks supported pint versions.

Depends on #75, but can separate if desired.

Checklist

Please confirm that this pull request has done the following:

• Tests added
• Documentation added (where applicable)
• Changelog item added to changelog/

[lewisjared]

Ok after a few CI attempts the matrix of results that pass looks like:

matrix:
  os: [ "ubuntu-latest" ]
  # Testing the highest and lowest supported Python versions
  python-version: [ "3.10", "3.13" ]
  # Test all of the supported pint versions (including the latest)
  pint-version: [
    # The double quotes are needed to avoid parsing issues with the >= and < characters
    "'pint>=0.22,<0.23' 'numpy<2'",
    "'pint>=0.23,<0.24' 'numpy<2'",
    "'pint>=0.24,<0.25'",
    "'pint>=0.25,<0.26'",
    "'pint>=0.25'"
  ]
  exclude:
    # Known incompatibilities
    # Python 3.10 with pint 0.25 and above
    - python-version: "3.10"
      pint-version: "'pint>=0.25,<0.26'"
    - python-version: "3.10"
      pint-version: "'pint>=0.25'"
    # Python 3.13 with pint <0.24
    # Python 3.11 is the lowest version that supports pint 0.22/0.23
    - python-version: "3.13"
      pint-version: "'pint>=0.23,<0.24' 'numpy<2'"
    - python-version: "3.13"
      pint-version: "'pint>=0.22,<0.23' 'numpy<2'"

Going back to v0.22 is probably overkill as it was released 2 1/2 years ago.
If we follow SPEC-0 (which is suggested in #75),
v0.24 would be our minimum supported version (released 2024-06-07).
That should simplify the tests as anything older also requires numpy<2 which is now EoL too.

It should also be noted that using pdm with requires-python = ">=3.10" will block pint 0.25 from being installed as it requires Python 3.11.

@mikapfl @znicholls Any qualms about only testing SPEC-0 compatible deps? This is pretty feature complete so there are old versions people can install and keep working with if they need.

[mikapfl]

No concerns at all about only testing SPEC-0 compatible deps. We might not like it, but SPEC-0 is an established standard, and within scientific python development ecosystem, nobody cares about things which are out of the SPEC-0 support window. People focus on future enhancements above stability. We shouldn't swim against the tide but go with the flow.

[znichollscr]

No concerns at all about only testing SPEC-0 compatible deps for me too, Mika makes good points.

In the latest copier template, there is quite some work done to add better support for checking min and max supported versions of other things. What you've done here is more thorough for Pint though, so maybe a better solution for a package like this which is such a thin wrapper (effectively).

[znichollscr]

Copier template dependency pinning and testing stuff: https://gcages.readthedocs.io/en/latest/further-background/dependency-pinning-and-testing/