def test_oddity():
"""Test oddities of tail."""
data = iter('ABCDE')
# specifying None as the length consumes the whole iterator
res = tail(None, data)
assert next(res) == 'A'
assert list(res) == ['B', 'C', 'D', 'E']
assert list(data) == []
data = ()
# specifying None as the length consumes the whole iterator
res = tail(None, data)
assert list(res) == []
def test_normal():
"""Test tail."""
# tail less than data
data = iter('ABCDE')
res = tail(3, data)
assert next(res) == 'C'
assert list(res) == ['D', 'E']
assert list(data) == []
# tail exact count of data
data = iter('ABCDE')
res = tail(5, data)
assert next(res) == 'A'
assert list(res) == ['B', 'C', 'D', 'E']
assert list(data) == []
# tail more than data
data = iter('ABCDE')
res = tail(7, data)
assert next(res) == 'A'
assert list(res) == ['B', 'C', 'D', 'E']
assert list(data) == []
# tail nothing
data = iter('ABCDE')
res = tail(0, data)
assert list(res) == []
assert list(data) == []
# empty but request some
data = ()
res = tail(3, data)
assert list(res) == []
# empty and request none
data = ()
res = tail(0, data)
assert list(res) == []
