Re: atf for libcurses

[Brett Lymn <blymn%baea.com.au@localhost>]

On Wed, Nov 03, 2010 at 01:00:08PM +0000, Antti Kantee wrote:
> 
> Awesome!  Soon I'll have the courage to touch curses and be sure
> I didn't break anything.
> 

Well, that is the whole idea of doing this :)

> Apologies if I missed it, but I didn't find how to create the
> expected output files.  The ones I did look at looked, hmm, cryptic,
> so if there some tool to create an output check file which verifies
> that "hello" is printed in exactly the right place on the screen?
> 

Sorry for arm waving over that.  This is probably the hardest bit at
the moment.  What I don't want to do is automate capturing current
output because there may be lurking bugs and we would just enshrine
them into a test which I think is bad.

What I have done is set up a custom terminfo database for a terminal
called "atf", most of the terminfo output sequences are mapped to
their names.  If you look in the source files at the atf.terminfo file
you will see what I mean.  When curses uses the terminfo capabilities
they will be emitted as their names.  So the output stream should be
somewhat readable.

What I have been doing so far is setting the check file to /dev/null
and running the director in verbose mode (-v) which will tell you what
characters in the output stream were mismatched.  Having a look and
think about the output stream and if I believe it correct then putting
that sequence into a check file.

Note that the common sequences can be put into a single check file and
in the test file you can use the "include" directive to check for
common sequences.  An example of this is the initialisation sequence
for curses, I have a "curses_start" file in tests that is included
"curses_getch" which means the normal startup sequence is validated
before we do the getch work.

> Also, can this scheme be extended to curses applications (say, vi)
> and even further to similar applications which don't necessarily
> use curses?
> 

Yes, I think this is doable.  In fact I think it is almost there.  I
have had a bit of a rethink about how I do the output validation.  At
the moment the director looks for a set of function calls that it has
been told will result in output and expects an extra argument to that
call which is the check file.  I think this is a bit limiting now and
that I should introduce a new keyword, something like "validate" or
"verify_output" that will use the check file and perform the stream
comparisons.  If I do this then it would be a matter of doing a new
slave that can exec a program and drive it using the "input"
directives.  Definitely worth thinking about.

> (and finally, do you have a script which ascends in nethack ?)

Given the last time I played rogue my dog bit me and I went blind from
drinking some random potion... I think not.

-- 
Brett Lymn
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