Re: Splitting some erc tests

[Lars Ingebrigtsen <larsi@gnus.org>]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> My bet is that they aren't.  But IIRC the tests aren't run in the order
> in which they appear in the file, so I suspect that in *most* cases they
> are indeed sufficiently independent for your parallelism use-case.
> And those that aren't should be fixed accordingly.

I've done some slight testing, and it seems to work OK.  I've extended
ert-run-tests-batch-and-exit to take a "modulo" parameter to select the
nth test, and then you can pass that in from the Makefile.

However, I'm a bit lost as to how to express this stuff in the Makefile
itself.  If we're running without "-j<large-num>", then we don't want to
do this, but that information doesn't seem to be available without
something like this?

  https://blog.jgc.org/2015/03/gnu-make-insanity-finding-value-of-j.html

We'd also just want this for a select number of the tests, and the tests
are run as such:

%.log: %.elc
	$(AM_V_GEN)${MKDIR_P} $(dir $@)
	$(AM_V_at)HOME=$(TEST_HOME) $(emacs) \
	  -l ert ${ert_opts} -l $(testloadfile) \
	  $(TEST_RUN_ERT)

What would be the most convenient way to have a different rule for a set
of named tests?  I was first thinking of the moral equivalent of 

%.log: %.elc
       for i in `seq $jobs`; do
         $(emacs) ... (ert-run-tests-batch-and-exit ... $i $jobs) &
       done > $*.log

but that goes against the Make grain -- Make should control the
parallelism, of course.  So a number of rules like:

%.log-1: %.elc
       $(emacs) ... (ert-run-tests-batch-and-exit ... $* $jobs)

or something...  but...  this is way out of my Makefile comfort zone.

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