def test_iffy():
assert map(iffy(_ % 2, _ * 2, _ / 2), [1, 2, 3, 4]) == [2, 1, 6, 2]
assert map(iffy(_ % 2, _ * 2), [1, 2, 3, 4]) == [2, 2, 6, 4]
assert map(iffy(_ * 2), [21, "", None]) == [42, "", None]
assert map(iffy(_ % 2, _ * 2, None), [1, 2, 3, 4]) == [2, None, 6, None]
def test_juxt():
assert juxt(__add__, __sub__)(10, 2) == [12, 8]
assert map(juxt(_ + 1, _ - 1), [2, 3]) == [[3, 1], [4, 2]]
def test_iffy():
assert map(iffy(_ % 2, _ * 2, _ / 2), [1,2,3,4]) == [2,1,6,2]
assert map(iffy(_ % 2, _ * 2), [1,2,3,4]) == [2,2,6,4]
assert map(iffy(_ * 2), [21, '', None]) == [42, '', None]
assert map(iffy(_ % 2, _ * 2, None), [1,2,3,4]) == [2, None, 6, None]
def test_iffy():
assert map(iffy(_ % 2, _ * 2, _ / 2), [1,2,3,4]) == [2,1,6,2]
assert map(iffy(_ % 2, _ * 2), [1,2,3,4]) == [2,2,6,4]
assert map(iffy(_ * 2), [1, '', None, '2']) == [2, '', None, '22']
assert map(iffy(_ % 2, _ * 2, None), [1,2,3,4]) == [2, None, 6, None]
def test_juxt():
assert juxt(__add__, __sub__)(10, 2) == [12, 8]
assert map(juxt(_ + 1, _ - 1), [2, 3]) == [[3, 1], [4, 2]]
