def test1():
"""Test the Ring data structure."""
from Ring import Ring
a = Ring([0,1,2])
assert a[0] == 0
assert a[1] == 1
assert a[2] == 2
assert a.first() == 0
assert a.last() == 2
a.turn()
assert a[0] == 1
assert a[1] == 2
assert a[2] == 0
assert a.first() == 1
assert a.last() == 0
a.turn()
assert a[0] == 2
assert a[1] == 0
assert a[2] == 1
assert a.first() == 2
assert a.last() == 1
