Test #9 (lines 33-34) is named “two_chatty_people_make_a_good_pairing” but only one of the two people (Gustavo) is “chatty”, the other one (Jaime) is not.
That makes this test #9 equivalent to test #10 “one_chatty_person_make_a_good_pairing_with_anyone” where Valeria is “chatty” but Jaime is not.
I guess the intention of test #9 was to have two people who are both “chatty”, i.e. Gustavo and Valeria.
I’d suggest this change of line 34:
- pairing(gustavo, jaime).
+ pairing(gustavo, valeria).
You could also consider adding another test where the second person is “chatty” but the first person is not.
test(anyone_makes_a_good_pairing_with_a_chatty_person, condition(pending)) :-
pairing(jaime, gustavo).
But maybe I’m missing something here, I’m very bad at Prolog.