Test

`parallelize` sets numba cores to 1 #1591

Job	Run time
test (3.12, ubuntu-latest)	11m 10s
test (3.11, ubuntu-latest)	10m 20s
test (3.10, ubuntu-latest)	10m 35s
test (3.12, macos-latest, --pre, Python 3.12 (pre-release))	16m 20s
	48m 25s

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