Add shell detection

[ofek]

Resolves #3

[ofek]

@AlJohri Would you mind testing zsh? @jaraco Would you mind testing xonsh?

I plan to add a Docker env for each shell to tests but I won't have time this week

[jaraco]

I'm getting an error when it runs, though it does seem to have added the expected lines:

userpath ofek/detect $ git-id                                                                                                                                                  
3cc42f8
userpath ofek/detect $ tox --notest                                                                                                                                            
GLOB sdist-make: /Users/jaraco/code/public/userpath/setup.py
python create: /Users/jaraco/code/public/userpath/.tox/python
python installdeps: pytest
python inst: /Users/jaraco/code/public/userpath/.tox/.tmp/package/1/userpath-1.1.0.zip
python installed: atomicwrites==1.3.0,attrs==19.1.0,Click==7.0,more-itertools==7.0.0,pluggy==0.11.0,py==1.8.0,pytest==4.5.0,six==1.12.0,userpath==1.1.0,wcwidth==0.1.7
___________________________________________________________________________________ summary ___________________________________________________________________________________
  python: skipped tests
  congratulations :)

userpath ofek/detect $ .tox/python/bin/python -m userpath append foo/bar                                                                                                       
An unexpected failure seems to have occurred.
userpath ofek/detect $ tail -n 3 ~/.xonshrc                                                                                                                                    

# Created by `userpath` on 2019-05-13 12:20:01
$PATH.append(r"/Users/jaraco/code/public/userpath/foo/bar")

[ofek]

@AlJohri @jaraco @cs01 So, here's what I've done:

• Implemented the ability to select particular shells to modify, defaulting to auto-detection, and if that fails, to sh and bash
• We now require https://github.com/nir0s/distro as a dependency to handle https://github.com/ofek/userpath/issues/3#issuecomment-492491977 and other issues like it in future
• Made integration tests via Docker for the login & non-login version of every shell, with full support for code coverage. Currently, we just test Debian (Stretch) but adding other Dockerfiles would be trivial

I'd appreciate it if you could test this once more, then I'll merge and release!

[jaraco]

Looking good!

userpath ofek/detect $ git-id
6ace5e6
userpath ofek/detect $ tox --notest -qq
userpath ofek/detect $ .tox/python/bin/python -m userpath append foo/bar
Success!
userpath ofek/detect $ tail -n 3 ~/.xonshrc

# Created by `userpath` on 2019-06-21 20:28:07
$PATH.append('/Users/jaraco/code/public/userpath/foo/bar')

Couple of comments follow.

Should there be output for success? Unix conventions say don't emit anything on success, although maybe that's an old convention. You may be asked later to add a -q operator to suppress that output. I don't feel strongly about it.

At first, the help text had me thinking that the Windows behavior was unnecessarily special cased. In particular:

-a, --all-shells; Update PATH of all supported shells. This has no effect on Windows as that is the standard behavior.

This made me think that on Windows, it would attempt to modify the config of all these shells... then I realized that the reason "that is the standard behavior" means that environment settings always affect all shells, not that userpath will be modifying all supported shells. I'm not sure there's anything to do here, but I thought I'd share my momentary confusion.

Overall, no objections. Looks great to me.

[AlJohri]

I'll try and test this out early next week- apologies for the delay.

[ofek]

1.2.0 is now on PyPI 😄

@jaraco I incorporated your suggestions @AlJohri Can we proceed with the Homebrew PR now?