Fortran oo support with unittest

[krystophny]

This is a variant of #239 where I did some modifications on top of the great work of @danbeibei

1. Change from pytest back to unittest. Dependencies between tests are preserved as comments for later.
2. Change primary accuracy to real(kind=8) and pre-compute pi. I felt more confident with the "almost equal" asserts that work slightly differently in unittest.
3. Fix CI build failures for type_check example #242 due to small issues in Makefile.meson in some examples.

@jameskermode if this fits your requirements, it should be ready to merge -- ideally first #239 and than this one here.

[jameskermode]

Great, thanks, I'm happy to merge this - will do as you say and merge #239 first. Do you happen to know why the x86_64 wheel builds are getting cancelled?

[jameskermode]

Looks like this now needs some conflicts resolving before it can be merged. Will try to get to this later.

[krystophny]

Resolved the conflicts, no idea why this happened because the branch was based on #239 but looks fine for now.

[krystophny]

... about the macos x86_64 builds, I don't know, but it happend to me in all CI/CD jobs up to now. I checked in the action log and it says

The macOS-12 environment is deprecated, consider switching to macOS-13, macOS-14 (macos-latest) or macOS-15. For more details, see actions/runner-images#10721
GitHub Actions has encountered an internal error when running your job.

[krystophny]

... looks fine when hardcoding macos-13 instead of macos-latest on x86_64. macos-latest is not anymore supported there, see actions/runner-images#9741

[jameskermode]

Thanks for fixing that! I'll go ahead and merge this and the follow up PRs and then see where we are. Once all building correctly I'll do a new release.

[danbeibei]

Great, thanks @krystophny for doing the rebase work!