TST: Provide random data generators to tests

[jhlegarreta]

Provide random data generators to tests.

[jhlegarreta]

Cross-ref #71 (comment). A few comments:

• When PR REF: Refactor filters into filtering #71 is merged on main, I will refactor the remaining methods here.
• For now, we will content ourselves loading the HCPh gradients: https://github.com/nipreps/nifreeze/pull/85/files#diff-7dae78a00d8d69422a3bfbde96c7c5d794eede504a0df763853896a1ba1b5ff2R241. As we test and develop further the tool, the boolean parameter may become an enum instance that will enable choosing between generating a randgom gtab, or loading the files corresponding to the gradient schemes available on the repo data.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 41.79%. Comparing base (385dabd) to head (63e6f37).
Report is 4 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main      #85       +/-   ##
===========================================
- Coverage   70.28%   41.79%   -28.50%     
===========================================
  Files          23       23               
  Lines        1060     1060               
  Branches      128      128               
===========================================
- Hits          745      443      -302     
- Misses        271      602      +331     
+ Partials       44       15       -29     

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[jhlegarreta]

Re #85 (comment) let's have this merged in order to make some progress, and I will refactor the necessary parts in a new PR after PR #71 gets merged.

[jhlegarreta]

Merging. CI failures are unrelated to these changes (x-ref issue #149).

[oesteban]

https://github.com/nipreps/nifreeze/actions/runs/15379441057/job/43268290249#step:11:411 looks like unrelated to #149 and introduced with this PR.

For the time being, I'd suggest not merging PRs failing for #149 and re-trigger them until the stanford dataset goes through.

[oesteban]

In fact, the CI failure on this PR (https://github.com/nipreps/nifreeze/actions/runs/15367033028/job/43261539274#step:11:326) is unrelated to #149.