Add tests of utility functions #182

Job	Run time
initial_checks / Load tox environments	5s
initial_checks / codestyle (ubuntu-latest)	33s
deploy-examples	0s
tests / Load tox environments	6s
tests / py39-test-all (ubuntu-latest)	3m 58s
tests / py310-test-all (ubuntu-latest)	3m 49s
tests / py311-test-all (ubuntu-latest)	3m 40s
tests / py312-test-all (ubuntu-latest)	4m 15s
tests / py312-test-qt (ubuntu-latest)	3m 14s
tests / py312-test-jupyter (ubuntu-latest)	3m 4s
tests / py39-test-all (macos-12)	9m 27s
tests / py310-test-all (macos-latest)	5m 36s
tests / py311-test-all (macos-latest)	5m 55s
tests / py312-test-all (macos-latest)	6m 6s
tests / py312-test-qt (macos-latest)	5m 6s
tests / py39-test-all (windows-latest)	6m 44s
tests / py310-test-all (windows-latest)	7m 28s
tests / py311-test-all (windows-latest)	6m 49s
tests / py312-test-all (windows-latest)	7m 18s
tests / py312-test-qt (windows-latest)	5m 44s
tests / py312-test-jupyter (windows-latest)	4m 51s
	1h 33m 48s

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