re-fix cythonize

[bjlittle]

Addresses #34 (again, sorry)

Closes #98

[bjlittle]

@jswhit The coverage is back to ~87%, see the travis-ci logs for this job, which is what we expect.

In summary, the setup.py will only cythonize if Cython is available (and it is for the travis-ci test environment, hence the coverage works correctly), otherwise setup.py won't cythonize the Extension, as per the previous behaviour.

[jswhit]

Hopefully it still will cythonize the extension even if cython is not installed, since cython is in setup_requires. (that was the source of the problem reported in issue #34) What is cythonize doing that distutils Extension doesn't to enable the coverage stuff to work? Is it not using the compiler_directives and language_level kwargs?

[bjlittle]

Not sure... compiler_directives and language_level are kwargs to cythonize rather than Extension.

Seems like those kwargs passed to Extension are not getting passed down into the setuptools internal call to cythonize (or whatever it's doing to magically build cftime on the fly).

But to be honest, I don't think that this is a problem that we need to solve. We only want test coverage to work in travis-ci, and that's the case now with the changes in this PR. As on travis-ci we ensure that Cython is available in the environment prior to the explicit cythonize call in setup.py.

We also don't want setup.py to barf by importing Cython when it's not available (prior to the setup call), and that's the use case for other users.... but in their case they don't need or care about test coverage, they just want cftime to build and install. If they do care about test coverage (then they must be a developer) so it's not unreasonable for us to ask them to install Cython.

Seems like a happy compromise to me. Thoughts?

Am I missing a trick here @jswhit ?

[jswhit]

Agreed. I'll see if I can test in an environment without cython installed, just to make sure it works as expected.

[jswhit]

Works as expect in a environment without cython, merging now....

[bjlittle]

Thanks @jswhit and apologies for the carnage...

[jswhit]

no worries, casualties were very minor.