Allow tests to run on MacOS.

[janiversen]

MacOS is a little bit different than Linux basically it puts "/private" in front of a number of standard paths.

I added conftest.py for now just with 2 tests IS_DARWIN and IS_WINDOWS, but I believe there are more common items between the test files, that could later go into conftest.py

I changed a few test in a way that the difference in path is very clear, which I prefer because "you see what you get" :-) but if there is a preference for a central function I can easily make that.

I am (currently) not trying to make mopidy work on MacOS, that would take a lot more testing, I just want a clean environment so that I can test locally before submitting my bug fixes.

[janiversen]

I knew it, I am so used to having a precommit hook, that I forgot to run lint, let me just do that.

[kingosticks]

I'd personally prefer to not think about what platform I am running on when writing tests, it's just unrelated noise. I'd much rather hide this in a helper.

However, I am a bit surprised we also we need this. I don't have an MacOS system but isn't /tmp normally a symlink to /private/tmp so it'll just work in most cases. For those that don't, can we just .resolve() the path first?

Edit: clarity

[janiversen]

Just to be clear we talk about MacOS not IOS!

Getting pytest and not to mention python itself, is a major challenge.

/tmp and /private/tmp are not symlinked on Mac, when using pathlib which tries to give the "real" path.

Let me see if I can do magic with .resolve() or alternatively I can make a helper making it (nearly) invisible.

Btw. I agree with you, I too hate having platform specific items in test, in my other project we have managed to reduce it to just a couple of tests.

[janiversen]

Forgot one comment. I have only changed where needed (I live by the rule "never touch a running system"), however in most cases it was less changed to do it generally in the setup().

[janiversen]

Found the culprit !!!

It is actually .resolve() that follows symlinks and return the physical path.

Please see def expand_path(path) in path.py, I added a couple of tmps to debug better:

    # original statement:
    return pathlib.Path(path).expanduser().resolve()

    # my additions:
    path = '/var/folders/r_/ln...gn/T/tmpkqzcbhdb/test'
    tmp1 = pathlib.Path(path) 
    tmp2 = tmp1.expanduser()
    tmp3 = tmp2.resolve() # tmp3 == PosixPath(

    # tmp1 == PosixPath('/var/folders/r_/ln...gn/T/tmpkqzcbhdb/test')
    # tmp2 == PosixPath('/var/folders/r_/ln...gn/T/tmpkqzcbhdb/test')
    # tmp3 == PosixPath('/private/var/folders/r_/ln...gn/T/tmpkqzcbhdb/test')

Now that I know what the problem is, let me see how I can fix it.

I do not want to change the production code, only the test code.

[janiversen]

@kingosticks Thanks for the feedback

I like positive review comments...they make you think and not just do what you usually do.

I have reworked the patch and removed all the platform dependent pars.

I hope you like it, or tell me what I would change. It is a little bit strange to call .resolve(), I think it should be moved down in the production code, but at a much later date.

Your review comments gave me the opportunity to start debugging the core, I will continue with that for my next PR (slowly learning more about the code and the project).

[janiversen]

@kingosticks forgot to mention, it is ready for another review and hopefully a merge, when you have time