Depends what type of animal it is. If it is a domestic animal, such as a cat or dog; I believe that they should NOT by any means be tested upon, as they are believed to have some sort of intelligence. At least more than most non-domestic animals. Dogs in particular are actually believed to be capable of loving.
However if it is a sewer rat, racoon, or something of that nature, then I think they should absolutely be allowed to perform some tests using them.
EDIT: Omg some of these pictures have me almost crying
