def test_sort(self):
a = ((1, 'a',), (2, 'b'), (3, 'c'))
b = ((10, 'Z',), (9, 'Y'), (8, 'X'))
c = ((1, 'Z',), (3, 'Y'), (2, 'X'))
dla = IntDisplayList(a)
dlb = IntDisplayList(b)
dlc = IntDisplayList(c)
assert dla.values() == ['a', 'b', 'c']
dlb_s = dlb.sortedByValue()
assert dlb_s.values() == ['X', 'Y', 'Z']
dlc_s = dlc.sortedByKey()
assert dlc_s.values() == ['Z', 'X', 'Y']
