10.46.3.2 Nondeterminate Tests

Nondeterminate tests succeed zero or more times. Their results can be tested using findall/3 followed by a value-check. The following are equivalent tests:

     test(member5) :-
             findall(X, member(X, [a,b,c]), Xs),
             Xs == [a,b,c].
     
     test(member6, true(Xs == [a,b,c])) :-
             findall(X, member(X, [a,b,c]), Xs).