Explicit error if _DEFAULT_LOCALE_PATH is None

[eldipa]

Try to use __file__ if possible but do not crash if not.

Instead, when activate is used and no explicit path is given, raise an
exception explaining why.

A better alternative could be use resource_path
(https://docs.python.org/3/library/importlib.html#importlib.abc.ResourceReader)
to find the directory of 'locale'.

Unfortunately Python (at least 3.7) only allows to access to files
and not folders so we cannot access to 'locale' (a folder)

Closes #81

Changes proposed in this pull request:

• Do not crash if __file__ does not exist
• Raise an exception if the default path is needed

[codecov-commenter]

Codecov Report

Merging #132 into master will decrease coverage by 0.71%.
The diff coverage is 50.00%.

@@             Coverage Diff             @@
##            master     #132      +/-   ##
===========================================
- Coverage   100.00%   99.28%   -0.72%     
===========================================
  Files            9        9              
  Lines          416      421       +5     
===========================================
+ Hits           416      418       +2     
- Misses           0        3       +3     

Flag	Coverage Δ
#GHA_Ubuntu	99.28% <50.00%> (-0.72%)	⬇️
#GHA_Windows	99.28% <50.00%> (-0.72%)	⬇️
#GHA_macOS	99.28% <50.00%> (-0.72%)	⬇️

Impacted Files	Coverage Δ
src/humanize/i18n.py	92.50% <50.00%> (-7.50%)	⬇️
tests/test_number.py	100.00% <0.00%> (ø)

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[eldipa]

The failing test is about formatting. I don't have problems to fix it, but I cannot make the lint work. Is any document about how to setup an environment for development for humanize?

[hugovk]

Thanks for the PR!

There's no docs about that, it'd be good to put it into a CONTRIBUTING.md.

Anyway, to do all the linting:

pip install pre-commit
pre-commit install  # optional, this is to enable the pre-commit linting and run when you commit, on just the staged changes
pre-commit run --all-files  # to run on all files now

[hugovk]

@eldipa I've created https://github.com/eldipa/humanize/issues/1 to fix the lint. Merging that will update this PR, then we can get a release out soon. Thanks!

[hugovk]

Thanks!