def test_normal_peek():
"""Test unique_everseen with peeking at iterable."""
# no key with all upper data
data = iter('ABAACCD')
res = unique_everseen(data)
assert next(res) == 'A'
assert next(data) == 'B'
assert list(res) == ['C', 'D']
assert list(data) == []
# no key with mixed data
data = iter('ABCcAD')
res = unique_everseen(data, lambda x: x.lower())
assert next(res) == 'A'
assert next(data) == 'B'
assert list(res) == ['C', 'D']
assert list(data) == []
# lower key with mixed data - note key is unchanged from first instance
data = iter('ABcCcCAD')
res = unique_everseen(data, lambda x: x.lower())
assert next(res) == 'A'
assert next(data) == 'B'
assert list(res) == ['c', 'D']
assert list(data) == []
# lower key with mixed data - note key is unchanged from first instance
data = iter('ABBcCcCAD')
res = unique_everseen(data, lambda x: x.lower())
assert next(res) == 'A'
assert next(data) == 'B'
assert list(res) == ['B', 'c', 'D'] # first B removed but second is still
# there
assert list(data) == []
def test_normal():
"""Test unique_everseen."""
# no key with all upper data
data = iter('AAAABBBCCDAABBB')
res = unique_everseen(data)
assert next(res) == 'A'
assert list(res) == ['B', 'C', 'D']
assert list(data) == []
# no key with mixed data
data = iter('AAAABBBcCcCDAABBB')
res = unique_everseen(data)
assert next(res) == 'A'
assert list(res) == ['B', 'c', 'C', 'D']
assert list(data) == []
# lower key with mixed data - note key is unchanged from first instance
data = iter('ABBCcAD')
res = unique_everseen(data, lambda x: x.lower())
assert next(res) == 'A'
assert list(res) == ['B', 'C', 'D']
assert list(data) == []
# lower key with mixed data - note key is unchanged from first instance
data = iter('ABBcCcCAD')
res = unique_everseen(data, lambda x: x.lower())
assert next(res) == 'A'
assert list(res) == ['B', 'c', 'D']
assert list(data) == []
# empty
data = ()
res = unique_everseen(data)
assert list(res) == []
