Run (some) tests more automagically?

[Lars Ingebrigtsen <larsi@gnus.org>]

I wonder whether anybody's considered making "make" run some tests.

It's a recurring issue that we make a change, and then we forget to run
the test suite.  I mean, it's not a major problem, because it'll
eventually get run by somebody, but I'd feel more confident in my own
changes if I'd remember to run more tests more often.

The reason we don't is because we don't want to wait for some minutes
while running the entire suite.

So here's today's not-thought-out-at-all idea: Since tests for
lisp/foo.el live in test/lisp/foo-tests.el, could we add some Makefile
magic to automatically run foo-tests.el if lisp/foo.el has been changed?
Running just those tests shouldn't take too much time, and would
probably cover 93% of the relevant code changes for foo.el.

One disadvantage to doing this (if we find a way) is that "make
foo-tests" is often very noisy, so we'd need a way to run tests silently
and just report if anything actually fails unexpectedly, I guess.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no