def test_invert_linear(self):
s = Span(5, 15, 20, False)
s1, s2 = s.invert()
assert s1.a == 0
assert s1.b == 5
assert s2.a == 15
assert s2.b == 20
def test_invert_cyclic(self):
s = Span(5, 15, 20, True)
i1 = s.invert()[0]
assert i1.a == 15
assert i1.b == 5