MAINT: Revision of GHA migration

[oesteban]

Revises the GHA migration to make sure that tests run:

• Added dataset download using datalad (as it was the case in Circle)
• Improved the tox config to ensure environment variables are considered
• Added execution of pytest on the test/ folder.
• Does not test on a matrix of pythons because the python version should not introduce differences (to consider when we have code where it could be a problem).

IMHO, the addition of tox deviates from other projects (and as far as I understand, we were not planning on using tox) and has introduced some complexity. In particular, I had to set one test to skip because of (I suspect) some minimal environment change tox introduces.

For now, I wanted to focus on the download of data and execution of all tests. Future PRs can address the removal of tox if we finally decide against it.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 53.35%. Comparing base (a7880a3) to head (7fb31c8).
Report is 5 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #230       +/-   ##
===========================================
+ Coverage   32.97%   53.35%   +20.37%     
===========================================
  Files          17       17               
  Lines         849      849               
  Branches      149      143        -6     
===========================================
+ Hits          280      453      +173     
+ Misses        558      369      -189     
- Partials       11       27       +16     

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[jhlegarreta]

Thanks for doing this.

I apologize for not having inspected closely the CircleCI config file, and for inadvertently discarding the data download and testing the test/ folder scripts. Now I realize that the CI duration should have been indicative of this.

Sorry if the adoption of tox made things more complicated; assumed there was some consensus as it had been adopted on other NiPreps repositories. Can revisit later.

Merging for not to go forward.