I remember my grandmother doing the baked paper test on the 'range' (which may or may not have been a wood fueled AGA) for the little oven, specifically, just before one of the winter-born litters of kittens was popped into it for a few minutes to 'get them going'.

If the paper came out brown, the kittens went in the bottom oven, if it was still white, they went in the little oven. They never went in the big oven, or in the pot on the top.

LTS