Test suite for gptel

To run this suite, load all gptel elisp files, then all the elisp at the root of this repo into Emacs and run ert.

I populate this repo as a gptel submodule in the directory test, then run make from gptel’s directory:

.PHONY: test
test:
	git submodule update --init --recursive
	cd test && emacs -Q -L .. -L . \
	$$(find .. -mindepth 1 -maxdepth 1 \( -name '.*.el' -prune -o -name '*.el' -type f -printf ' -l %p' \)) \
	$$(find .  -mindepth 1 -maxdepth 1 \( -name '.*.el' -prune -o -name '*.el' -type f -printf ' -l %p' \)) \
	-l ert --batch -f ert-run-tests-batch-and-exit

Modify as appropriate.