TST: adding isolated build test

[henryiii]

Pulled out of 175.

[henryiii]

Is there a better test than scipy-like? I think part of the problem is that this is getting an SDist of something that needs to build (with setuptools, you can see it trying to get setuptools on Cygwin), like maybe NumPy or something.

[dnicolodi]

scipy-like requires Cython to build. As you cannot use the published wheel for Cython and Cython uses setuptools as build system, you need to get setuptools too. IIRC I already expressed dubs regarding choosing this particular test package. purelib-and-platlib may be a better choice.

[henryiii]

FYI, this fails on Cygwin in this branch (no ninja package), and passes in #175 - it's great to see this test does exactly what is supposed to do! :)

[henryiii]

You added build to the extra-requires and it is sufficient.

Not for Sage CI, actually. Hopefully I fixed it by adding python-build.

[henryiii]

meson dist is still broken. It's building meson-python successfully from SDist, it's just trying to make this package (I'm guessing outside of a git repo) and breaking. Is there a way to use meson dist outside a git repo? Actually, I bet in_git_repo_context() has something to do with it. I'll look into it tomorrow.

[eli-schwartz]

Is there a way to use meson dist outside a git repo?

No, because meson dist internally runs git archive, plus additional handling for subprojects (which either use git and are treated the same, or else don't use git and are copied entirely on the assumption that subprojects/*/ is effectively read-only).