bug#51037: [PATCH] Make `print-level` & `print-length` customizable in ERT batch tests

[Michael]

Hey Lars,

> > Sorry to chime-in late, but my patch does _not_ affect the
> > printing of backtraces, just results. That said, I do agree 
> > with
> > Eli about the truncated backtraces often being useless; what do
> > you think of another variable controlling
> > that... `ert-batch-full-backtraces` or something?
>
> I'm not sure I quite follow you here -- the original patch would 
> make
> the backtraces printed by ert more complete, wouldn't they?

Only when comparing _results_. Say I have test code like:

   (let ((a (<some complex list>)
         (b (<another complex list>))))
     ...
     (should (equal a b))

My changes would case the error message from the failed `should`
invocation to print `a` & `b` more fully (i.e. with fewwer
ellipses).

The backtrace logic is separate, and un-touched by my patch as
submitted (tho of course I can change that).

--
Michael <sp1ff@runbox.com>