t1 _ ((Leaf new) string: 'hi').
t2 _ ((NaryNode new) array: {'there'. 'world'}).
t3 _ ((BinaryNode new) left: t1 right: t2).
t3 firstAlphabetical "should evaluate to 'hi '"

t4 _ (Leaf new) string: ((FunnyNumber new) num: 7).
t5 _ (NaryNode new) array: {((FunnyNumber new) num:8). ((FunnyNumber new) num:9)}.
t6 _ (BinaryNode new) left: t4 right: t5.
(BinaryNode concatAll: t6 after: ((FunnyNumber new) num: 0)) num "should evaluate to 24"