Re: Testing redisplay code in batch

[Stefan Monnier]

>> So I'm ideally looking for a way to convince Emacs's internals to
>> perform redisplay as if there were "real" windows.  I don't need to
>> "see/display" the result, OTOH because I only need to test things like
>> `window-start` and `window-end` after calling `redisplay`.
>
> I think it is best to define the capabilities required from such a
> test harness.  What you say about seems to hint that you only intend
> to look at stuff exposed to Lisp.  If that is indeed the case, it
> could be easier to provide, but many aspects of the display engine
> cannot be tested this way, since only a small fraction of that is
> exposed to Lisp.

Indeed.  In the past I was thinking (abstractly) of much more demanding
circumstances, but for this specific test, all I need is to know the
`window-start`, so the corresponding data is already exposed to Lisp.
I don't know if that makes it easy enough to implement it without
significant work.


        Stefan