TST: Option to disable using C-extension for debugging

[pllim]

Maybe sometimes we want to see if tests behave the same with or without C-extensions.

[codecov]

Codecov Report

Attention: Patch coverage is 91.66667% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 80.35%. Comparing base (49f8c89) to head (8424bd7).

Files	Patch %	Lines
spherical_geometry/__init__.py	87.50%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #268      +/-   ##
==========================================
+ Coverage   80.33%   80.35%   +0.01%     
==========================================
  Files           5        5              
  Lines        1017     1023       +6     
==========================================
+ Hits          817      822       +5     
- Misses        200      201       +1     

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[pllim]

OK now the jobs ignoring C-ext sees the errors #265 is trying to fix.

If you want this, please SQUASH AND MERGE.

[mcara]

I think we need this. Thanks! However, I think I need to fix failing Python version of the C code first. So let's wait with merging a little.

[pllim]

I rebased and cleaned things up. I think this is ready, but if #271 gets merged first, then I will have to rebase again.

[pllim]

For the record, another option I considered was introducing astropy.config for this package. It is more Pythonic, cleaner, and allow context manager, etc, but I decided that was way overkill for something that is only used for debugging.

Also see: https://docs.astropy.org/en/latest/config/index.html

[mcara]

Wouldn't it be easier to just not build math_util in setup.py?

[pllim]

just not build

How do you do that conditionally, on-demand?

[jhunkeler]

I think we need this.

I agree. The ability to test the python code and math_util functions without rebuilding the package will let us know immediately when one, the other, or both are failing. Declaring HAS_C_UFUNCS once in __init__.py is a nice because we don't have to track down try/except blocks if we want to change the import behavior in the future.

[mcara]

just not build

How do you do that conditionally, on-demand?

Modify Extension in:

spherical_geometry/setup.py

Lines 115 to 119 in 49f8c89

	setup(
	ext_modules=[
	Extension('spherical_geometry.math_util', sources, **ext_info)
	],
	)

depending on the environment variable value

Requires re-building but isn't it what is done anyway for each CI test?

[pllim]

Re: #268 (comment)

I don't see how that is simpler than what I am proposing.

[pllim]

Also, what I am proposing here allows you to test with and without C-extension locally without rebuilding, as @jhunkeler said above.

[mcara]

Re: #268 (comment)

I don't see how that is simpler than what I am proposing.

Because it is a single change in a single module.