code/modules/unit_tests/~nova/character_preview_glow.dm

/proc/character_preview_glow_test_body	A preview body from preferences: lit is a lizard with emissive eyes and a glowing chest marking.
/proc/character_preview_glow_test_lit_pixels	How many of a glow's pixels light what is under them: red (blooming) or green, through any blockers.
/datum/unit_test/character_preview_glow	Character setup's preview draws what glows only with the lights off and only for a look that has something to glow, on the drawing's own canvas, and a garment over a glowing marking hides its glow as the game does.