Add Cython coverage plugin

[oscarbenjamin]

This only works with a small patch to Cython.

You can install the patched Cython from my fork with:

pip install git+https://github.com/oscarbenjamin/cython.git@pr_relative_paths

(I am about to open a Cython PR from that branch.)

Then to make a coverage enabled build you need:

meson setup build -Dcoverage=true

Then to run the tests and measure coverage it is:

spin run -- coverage run -m flint.test
coverage report
coverage html

Ideally once Cython is patched we can somehow put this altogether as a spin coverage command to make it nice and easy.

I basically had to rewrite Cython's coverage plugin, largely from scratch. I think that the only part left from the original after I rewrote everything is the parse_cfile_lines function.

For now we can merge this to python-flint but ideally this would be upstreamed to either spin or Cython I think so I will follow up with that after.

[oscarbenjamin]

Then to make a coverage enabled build you need:

meson setup build -Dcoverage=true

Then to run the tests and measure coverage it is:

spin run -- coverage run -m flint.test
coverage report
coverage html

I've updated bin/coverage.sh to do all of these things.

[oscarbenjamin]

@GiacomoPope @Jake-Moss

This should make it possible to do coverage measurement with the meson build. For now my patched Cython is needed:

pip uninstall cython
pip install git+https://github.com/oscarbenjamin/cython.git@pr_relative_paths

Then

bin/coverage.sh

should give you the coverage report.

Let me know if it doesn't work.

[GiacomoPope]

Oh cool! I'll have a play tomorrow, although now I've added the two types on my TODO list I probably have other implementation things to help people with!

[Jake-Moss]

Wonderful work thanks! It's working for me