:- use_module(library(fld)). :- fld_object(person2, [name, age, gender, occupation, shoe_size]). :- begin_tests(flds_set). test(set_fields_set_exists) :- fld_template(person2, Frank), flds([name(frank),age(35),shoe_size(9)], Frank), flds_set([age(36), shoe_size(10)], Frank, OlderFrank), flds([age(36), shoe_size(10)], OlderFrank). :- end_tests(flds_set).