def test_oddity():
"""Test oddities of nth."""
# None gets the first element
data = iter('ABCDE')
res = nth(data, None)
assert res is 'A'
assert list(data) == ['B', 'C', 'D', 'E']
# None gets the first element but it's empty, no default
data = ()
res = nth(data, None)
assert res is None
# None gets the first element but it's empty, with default
data = ()
res = nth(data, None, 'X')
assert res == 'X'
def test_normal():
"""Test nth."""
# 0th element
data = iter('ABCDE')
res = nth(data, 0)
assert res == 'A'
assert list(data) == ['B', 'C', 'D', 'E']
# 2nd element
data = iter('ABCDE')
res = nth(data, 2)
assert res == 'C'
assert list(data) == ['D', 'E']
# last element
data = iter('ABCDE')
res = nth(data, 4)
assert res == 'E'
assert list(data) == []
# beyond data with no default
data = iter('ABCDE')
res = nth(data, 7)
assert res is None
assert list(data) == []
# beyond data with default
data = iter('ABCDE')
res = nth(data, 10, 'X')
assert res == 'X'
assert list(data) == []
# 0th element, empty with no default
data = ()
res = nth(data, 0)
assert res is None
# 2nd element, empty with no default
data = ()
res = nth(data, 2)
assert res is None
# 0th element, empty with default
data = ()
res = nth(data, 0, 'X')
assert res == 'X'
# 2nd element, empty with default
data = ()
res = nth(data, 2, 'X')
assert res == 'X'