First, thanks for doing this, it's greatly appreciated.
I think your test sounds good. Really, if you verify the camera boots and you can use the keyboard with both the canon and CHDK menus, that's 99%.
Some general suggestions:
The SD card lock logic is affected by this change, so make sure the canon firmware doesn't show the "card locked" message when running CHDK on a locked card.
You don't need to check chdkptp buttons and scripted key presses separately, one or the other is fine.
If you are testing with chdkptp, remember the canon firmware often ignores key presses either until your switch to rec mode, or send post_levent_to_ui(4484). The levent doesn't work on older cams, and there may be other camera specific quirks.
I wouldn't worry to much about rigorously testing every possible key. Do verify that you can get into alt mode using the physical key on the camera.
For the jogdial, you should both sending jogdial actions from script / chdkptp wheel buttons, and using the physical jogdial in the CHDK menu. When using the jogdial in the CHDK menu, the canon UI should NOT respond to the jogdial inputs.
There were some issues I noticed while doing the conversions that I wasn't comfortable trying to fix blind:
* ixus980_sd990 doesn't have the code to respond to jogdial inputs. Scripted jogdial should work. I should be able to come up with a test build with a full implementation.
* confusion about the cameras with the "feather" / "touch wheel" / "touch control dial" feature:
http://chdk.setepontos.com/index.php?topic=12245.msg121374#msg121374 - the main thing is to check if the touch feature causes any problems with CHDK.
* synced remote probably doesn't work on s2is. I think regular remote should.
I think there were more, but I'll have to spend some time digging through my notes.
