test: add simple slice test to cuda

[martindurant]

Shows failure in the function I added and probably all following ones.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.06%. Comparing base (b749e49) to head (afe4d61).
Report is 158 commits behind head on main.

Additional details and impacted files

see 106 files with indirect coverage changes

[martindurant]

cc @ianna