fix(kernels): fix lints & warnings in tests

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 81.71%. Comparing base (01ece1f) to head (205d731).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #189 +/- ## ========================================== - Coverage 81.71% 81.71% -0.01% ========================================== Files 36 36 Lines 5338 5337 -1 ========================================== - Hits 4362 4361 -1 Misses 976 976 ```

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