code/modules/unit_tests/~nova/custom_sprites/saved_styles.dm

/proc/custom_style_test_folder	A fresh temporary folder for one test's preference and sidecar files.
/proc/custom_style_test_cleanup	Deletes the preference and sidecar files a test wrote to `folder`.
/proc/custom_style_test_sidecar	A sidecar store whose last verified contents match the file written for a save test.