johnbuford,
What is with all the questions on antiquated, obsolete, expensive, slow, and hard to buy technology from the late 80's and early 90's? e.g.: EEPROMS, EPROMS, analog scopes from the 80's, old async SRAMs, and now PLDs.
Do you spend your days looking around on electronics history sites to come up with these questions?
Gal/Pal etc are all discontinued products of their respective manufacturers. Buying a Gal now involves going on Ebay/etc and hoping you don't get a tube full of ESD damaged, heavily used (reprogrammed), or reclaimed parts.
Basically the answers to your questions are:
"What are GAL and PAL chips used for"
Absolutely noting now days as there are cheaper, faster, and easy to buy alternatives.
and how can you test these types of chips
You don't...see the answer to the first question.