Update python setup logic

[krisfed]

I've consulted with the Python interface team and reworked the logic for python setup. Changes include:

1. Moving py.importlib.reload into a separate method, Zarr.pyReloadInProcess(). Reloading of the python module is only needed during development - when the python code is changed and MATLAB is using in-process python. In that case, the developer needs to do the following in order for the updates in the python code to be picked up:

clear classes
Zarr.pyReloadInProcess()

If they are using out-of-process python, they can just do

terminate(pyenv)

2. Instead of using py.ZarrPy to refer to the Python module, updated the code to always use the return of py.importlib.import_module('ZarrPy'). Using py.ZarrPy should normally work, but there seems to be some issue with that workflow at the moment (especially with out-of-process python). So using the return of py.importlib.import_module('ZarrPy') is currently more robust. We are ok to do multiple calls to py.importlib.import_module('ZarrPy') without any performance penalty, as it internally caches the module after the first call.

3. Added a test for the new Zarr.pyReloadInProcess() method. It is just a sanity check to make sure using the method does not break any functionality. Since we now have two tests for functions of Zarr class, created a separate tZarr file for those kinds of unit tests.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.09%. Comparing base (350881d) to head (a04a72a).
Report is 9 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #111      +/-   ##
==========================================
- Coverage   97.11%   97.09%   -0.03%     
==========================================
  Files           8        8              
  Lines         243      241       -2     
==========================================
- Hits          236      234       -2     
  Misses          7        7              

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[jhughes-mw]

Where is this called?

[jhughes-mw]

NM, I missed the tests. Is it only for the tests?

[krisfed]

This is for development convenience. If Python is in-process and we modify the Python code, this method can be used after clear classes to reload the Python module to pick up the code changes.

[jhughes-mw]

Ahhhh- you could do something like having a constant hidden property that cleans up and executes that function so clear classes would do this automagically.

[krisfed]

I've discussed different approaches with external interface team and didn't arrive to anything much cleaner, so time-boxed it to this solution. But will follow up with you offline to see if we can improve it.

[jm9176]

Thanks for updating the tests.