regression testsuite for the gui

[Nicola Pero]

I think we really need a regression testsuite for the gui library now.

We could at least test - 

 * basic allocation of objects, copying, etc works 

 * coordinate conversion routines (NSView etc);

 * tests for points inside rectangles etc (NSView etc again);

 * tests for getRow:column:forPoint: and the tons of other methods 
   for retrieving things from NSMatrix, NSMenu, NSBrowser etc, 
   either the selected one or etc (btw, this is quite important as it
   seems we are periodically breaking the same things in NSMatrxi 
   and NSBrowser ... things which could be regression-tested
   automatically)

 * I think if we are clever we can test more complicated stuff, real
   stuff I mean.
   For example, I noticed that deleting using backspace in a
   textfield doesn't really work any longer.  We can catch that 
   with an automated test: we create a window with two textfields in
   it.  in the first one, we insert programmatically `nico'.  In 
   the second one, we insert programmatically `nicola' and then 
   programmatically set the insertion point at the end and
   programmatically delete backwards two characters.  then, we set 
   the first responder to be, say, a third text field.  at this point,
   we grab the first textfield as an image, and the second textfield
   as an image, and we compare the two images.  if they are the same,
   the test is passed, otherwise something is wrong.
   Might this work ?  if it does, we could then eg write some
   regression tests for postscript path utilities this way etc

any comments ?