tests: fix parametrize patterns rejected by pytest 9.1.0

[leofang]

Summary

main has been red since pytest 9.1.0 landed on PyPI — every Test linux-* / Test win-* matrix entry fails at pytest collection time, before any actual test runs. Two unrelated latent bugs in our test code, both tolerated by older pytest but rejected by pytest 9.1.0's stricter parametrize validation:

Bug 1: trailing comma in parametrize name (cuda_core)

cuda_core/tests/test_utils.py:151 had:

@pytest.mark.parametrize("in_arr,", _cpu_array_samples())

The , inside the string was a stray. pytest 9 splits names on comma, ends up with one name but 3-tuple values, and fails collection with:

in "parametrize" the number of names (1):
  ['in_arr']
must be equal to the number of values (3):
  (665115599, 23133, 0)

Fix: drop the trailing comma.

Bug 2: indirect=True override of a fixture-level parametrize (cuda_bindings)

cuda_bindings/tests/test_nvfatbin.py has an arch fixture parametrized with params=ARCHITECTURES. Two tests overrode it via @pytest.mark.parametrize("arch", ["sm_80"], indirect=True). pytest 9 now rejects this as:

duplicate parametrization of 'arch'

Fix: extract the CUBIN-building logic from the CUBIN fixture into a _build_cubin(arch) helper, drop the indirect override on the two affected tests, and call the helper directly with "sm_80" (preserving the original intent — those tests intentionally used only sm_80, since target arch "75" must not match the CUBIN's arch).

Backwards compatibility

Both fixes are pytest-version-agnostic — pip pin (pytest>=6.2.4) doesn't need to change. Verified by collecting against three pytest versions (minimal repros, included below for reproducibility):

pytest	broken pattern 1	fixed 1	broken pattern 2	fixed 2
9.1.0	collection error	clean	collection error	clean
9.0.2	clean (tolerant)	clean	clean (tolerant)	clean
8.4.2	clean (tolerant)	clean	clean (tolerant)	clean

Reference

Affected CI runs on main:

• 8ba39e8: https://github.com/NVIDIA/cuda-python/actions/runs/27475559263
• 8ba39e8 (re-run): https://github.com/NVIDIA/cuda-python/actions/runs/27483372849
• ae1617d: https://github.com/NVIDIA/cuda-python/actions/runs/27487967018

Same pattern on my open #2210: https://github.com/NVIDIA/cuda-python/actions/runs/27489049015 — 38 Run cuda.core tests failures + 23 Run cuda.bindings tests failures all stem from these two collection errors.

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[rwgk]

I saw ... it can only get better!