
Hi Pauline,
Your best option is to go onto the breed club of your chosen breed and find out which health tests are relevant (hip scoring and eye testing are quite common across breeds, but some have other important issues which are breed specific ;) )
The tests will (or should) have been done on the parents :) That they have passed these tests is not a guarantee that the offspring will be automatically clear of an inherited health problem - but at least you will know that the breeder is doing their best to avoid breeding on a problem.
A breed club will be able to put you in touch with responsible breeders and also be able to offer valuable breed advice in general.
HTH meantime,
Teri :)