bug#22471: ert batch should print compile parsable error messages

[Eli Zaretskii]

> From: phillip.lord@russet.org.uk (Phillip Lord)
> Date: Wed, 27 Jan 2016 09:15:44 +0000
> 
> 
> Currently, when running in batch, ert prints out messages like so:
> 
> 
> Running 24 tests (2016-01-27 09:05:17+0000)
>    passed   1/24  buffer-string=
>    passed   2/24  buffer=
> ...
>    passed  22/24  sisyphus-test-with-find-file
>    passed  23/24  to-string
>    passed  24/24  with-temp-buffers
> 
> Ran 24 tests, 23 results as expected, 1 unexpected (2016-01-27 09:05:18+0000)
> 
> 1 unexpected results:
>    FAILED  crash-out
> 
> It would be nice to add some compilation-mode parsable data to this. So,
> something like
> 
> 
>    passed   1/24  buffer-string=  (in ./test.sisyphus-test.el:22:)

FWIW, I have never seen a test suite that displayed in
compilation-mode compatible format.  If we do that (and I'm
necessarily opposed to that), we'd be the odd one out, I think.