Closes #5285: alignment tests for arkouda.numpy.sorting

[ajpotts]

Add NumPy Alignment Tests for Sorting APIs

Summary

This PR adds a new NumPy alignment test suite for Arkouda sorting-related APIs. The goal is to ensure Arkouda behavior matches NumPy semantics across supported dtypes, shapes, axes, and edge cases.

What’s Included

• New test module: tests/numpy/alignment_verification/sorting_alignment.py
• Registration of the new module in pytest.ini so it runs as part of the standard test suite

APIs Covered

The new alignment tests compare Arkouda results directly against NumPy for:

• ak.sort
• ak.argsort (ascending and descending, stable behavior)
• ak.coargsort (validated against np.lexsort semantics)
• ak.searchsorted
  • scalar and vector inputs
  • side='left' and 'right'
  • x2_sorted=True/False
  • dtype mismatch and invalid shape handling

Test Matrix

• Dtypes: int64, uint64, float64
• Shapes: 1D, 2D, and 3D (where supported)
• Axes: 0, -1
• Execution guards: @pytest.mark.skip_if_rank_not_compiled used where multi-dimensional support depends on server configuration

Notable Details

• Uses NumPy’s stable argsort to ensure deterministic alignment for equal keys.
• Explicitly preserves NumPy scalar dtypes (e.g., np.uint64) for searchsorted to match Arkouda’s strict dtype checks.
• Validates not just permutation equality, but that applying argsort permutations actually sorts the data.

Motivation

This brings sorting APIs up to the same NumPy-alignment standard as existing operator and manipulation tests, strengthening confidence in Arkouda’s NumPy compatibility and catching regressions early.

Closes #5285: alignment tests for arkouda.numpy.sorting

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Additional details and impacted files

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[drculhane]

As far as I know (and I did a manual test), numpy normal returns np.float64. The astype(np.float64) isn't needed.

[drculhane]

This code implies that either numpy or arkouda can't handle a negative axis, but that's not correct. If you set axis_np to axis, and comment out lines 48 through 56, the test still passes.