Tests

I had forgotten pytest fixtures on some tests #75

Job	Run time
Verify Towncrier entry added	8s
ubuntu-latest, python3.9, defaults	23m 46s
macos-latest, python3.10, macos	33m 34s
ubuntu-latest, python3.8, old SciPy	20m 44s
ubuntu-latest, python3.9, no MKL	37m 47s
ubuntu-latest, python3.8, no Cython	19m 52s
ubuntu-latest, python3.10, Python 3.10	21m 23s
ubuntu-latest, python3.11, Python 3.11	22m 40s
windows-latest, python3.10, Windows Latest	32m 53s
Finalise coverage reporting	16s
	3h 33m 3s

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