def test_normal_peek():
"""Test pairwise with peeking at iterable."""
# recipes.pairwise with more than one element
data = iter('ABCD')
res = recipes.pairwise(data)
assert next(res) == ('A', 'B')
assert next(data) == 'C'
assert list(res) == [('B', 'D')] # C removed so B is paired with D
assert list(data) == []
def test_normal():
"""Test pairwise."""
# recipes.pairwise with more than one element
data = iter('ABCD')
res = recipes.pairwise(data)
assert next(res) == ('A', 'B')
assert list(res) == [('B', 'C'), ('C', 'D')]
assert list(data) == []
# recipes.pairwise with one element
data = iter('A')
res = recipes.pairwise(data)
assert list(res) == []
assert list(data) == []
# recipes.pairwise with empty
data = ()
res = recipes.pairwise(data)
assert list(res) == []
