Add some tests (#24) #22

Job	Run time
pytest / setup	3s
pytest / pytest (macos-latest, 3.8)	1m 16s
pytest / pytest (macos-latest, 3.9)	52s
pytest / pytest (macos-latest, 3.10)	56s
pytest / pytest (macos-latest, 3.11)	43s
pytest / pytest (macos-latest, 3.12)	36s
pytest / pytest (ubuntu-22.04, 3.8)	4m 37s
pytest / pytest (ubuntu-22.04, 3.9)	3m 36s
pytest / pytest (ubuntu-22.04, 3.10)	1m 48s
pytest / pytest (ubuntu-22.04, 3.11)	1m 29s
pytest / pytest (ubuntu-22.04, 3.12)	1m 13s
pytest / pytest (windows-latest, 3.8)	2m 39s
pytest / pytest (windows-latest, 3.9)	2m 32s
pytest / pytest (windows-latest, 3.10)	1m 59s
pytest / pytest (windows-latest, 3.11)	2m 18s
pytest / pytest (windows-latest, 3.12)	2m 11s
pytest / pytest (ubuntu-20.04, 3.6)	41s
	29m 29s

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