Tests

add tests for numpy backend #34

Job	Run time
Verify Towncrier entry added	7s
ubuntu-latest, python3.11, defaults	23m 48s
ubuntu-latest, python3.12, p312 numpy 2	24m 32s
ubuntu-latest, python3.10, p310 numpy 1.22	24m 0s
ubuntu-latest, python3.12, p312, numpy fallback	26m 4s
ubuntu-latest, python3.10, p310 no mkl	23m 21s
macos-12, python3.12, macos	34m 20s
macos-12, python3.11, macos - numpy fallback	35m 14s
windows-latest, python3.11, Windows	33m 55s
windows-latest, python3.10, Windows - numpy fallback	39m 48s
Finalise coverage reporting	11s
	4h 25m 20s

Provide feedback