Re: Test 041_checkpoint_at_promote.pl faild in installcheck due to missing injection_points

I wrote:
> Ugh.  The basic issue here is that "make install-world" doesn't
> install anything from underneath src/test/modules, which I recall
> as being an intentional decision.  Rather than poking a hole in
> that policy for injection_points, I wonder if we should move it
> to contrib.

... which would also imply writing documentation and so forth,
and it'd mean that injection_points starts to show up in end-user
installations.  (That would happen with the alternative choice of
hacking install-world to include src/test/modules/injection_points,
too.)  While you could argue that that'd be helpful for extension
authors who'd like to use injection_points in their own tests, I'm
not sure that it's where we want to go with that module.  It's only
meant as test scaffolding, and I don't think we've analyzed the
implications of some naive user installing it.

We do, however, need to preserve the property that installcheck
works after install-world.  I'm starting to think that maybe
the 041 test should be hacked to silently skip if it doesn't
find injection_points available.  (We could then remove some of
the makefile hackery that's supporting the current behavior.)
Probably the same needs to happen in each other test script
that's using injection_points --- I imagine that Maxim's
test is simply failing here first.

            regards, tom lane