mirror of
https://github.com/python/cpython.git
synced 2024-12-12 03:04:15 +08:00
248 lines
8.1 KiB
Python
248 lines
8.1 KiB
Python
# tests for slice objects; in particular the indices method.
|
|
|
|
import unittest
|
|
from test import support
|
|
from pickle import loads, dumps
|
|
|
|
import itertools
|
|
import operator
|
|
import sys
|
|
|
|
|
|
def evaluate_slice_index(arg):
|
|
"""
|
|
Helper function to convert a slice argument to an integer, and raise
|
|
TypeError with a suitable message on failure.
|
|
|
|
"""
|
|
if hasattr(arg, '__index__'):
|
|
return operator.index(arg)
|
|
else:
|
|
raise TypeError(
|
|
"slice indices must be integers or "
|
|
"None or have an __index__ method")
|
|
|
|
def slice_indices(slice, length):
|
|
"""
|
|
Reference implementation for the slice.indices method.
|
|
|
|
"""
|
|
# Compute step and length as integers.
|
|
length = operator.index(length)
|
|
step = 1 if slice.step is None else evaluate_slice_index(slice.step)
|
|
|
|
# Raise ValueError for negative length or zero step.
|
|
if length < 0:
|
|
raise ValueError("length should not be negative")
|
|
if step == 0:
|
|
raise ValueError("slice step cannot be zero")
|
|
|
|
# Find lower and upper bounds for start and stop.
|
|
lower = -1 if step < 0 else 0
|
|
upper = length - 1 if step < 0 else length
|
|
|
|
# Compute start.
|
|
if slice.start is None:
|
|
start = upper if step < 0 else lower
|
|
else:
|
|
start = evaluate_slice_index(slice.start)
|
|
start = max(start + length, lower) if start < 0 else min(start, upper)
|
|
|
|
# Compute stop.
|
|
if slice.stop is None:
|
|
stop = lower if step < 0 else upper
|
|
else:
|
|
stop = evaluate_slice_index(slice.stop)
|
|
stop = max(stop + length, lower) if stop < 0 else min(stop, upper)
|
|
|
|
return start, stop, step
|
|
|
|
|
|
# Class providing an __index__ method. Used for testing slice.indices.
|
|
|
|
class MyIndexable(object):
|
|
def __init__(self, value):
|
|
self.value = value
|
|
|
|
def __index__(self):
|
|
return self.value
|
|
|
|
|
|
class SliceTest(unittest.TestCase):
|
|
|
|
def test_constructor(self):
|
|
self.assertRaises(TypeError, slice)
|
|
self.assertRaises(TypeError, slice, 1, 2, 3, 4)
|
|
|
|
def test_repr(self):
|
|
self.assertEqual(repr(slice(1, 2, 3)), "slice(1, 2, 3)")
|
|
|
|
def test_hash(self):
|
|
# Verify clearing of SF bug #800796
|
|
self.assertRaises(TypeError, hash, slice(5))
|
|
self.assertRaises(TypeError, slice(5).__hash__)
|
|
|
|
def test_cmp(self):
|
|
s1 = slice(1, 2, 3)
|
|
s2 = slice(1, 2, 3)
|
|
s3 = slice(1, 2, 4)
|
|
self.assertEqual(s1, s2)
|
|
self.assertNotEqual(s1, s3)
|
|
self.assertNotEqual(s1, None)
|
|
self.assertNotEqual(s1, (1, 2, 3))
|
|
self.assertNotEqual(s1, "")
|
|
|
|
class Exc(Exception):
|
|
pass
|
|
|
|
class BadCmp(object):
|
|
def __eq__(self, other):
|
|
raise Exc
|
|
|
|
s1 = slice(BadCmp())
|
|
s2 = slice(BadCmp())
|
|
self.assertEqual(s1, s1)
|
|
self.assertRaises(Exc, lambda: s1 == s2)
|
|
|
|
s1 = slice(1, BadCmp())
|
|
s2 = slice(1, BadCmp())
|
|
self.assertEqual(s1, s1)
|
|
self.assertRaises(Exc, lambda: s1 == s2)
|
|
|
|
s1 = slice(1, 2, BadCmp())
|
|
s2 = slice(1, 2, BadCmp())
|
|
self.assertEqual(s1, s1)
|
|
self.assertRaises(Exc, lambda: s1 == s2)
|
|
|
|
def test_members(self):
|
|
s = slice(1)
|
|
self.assertEqual(s.start, None)
|
|
self.assertEqual(s.stop, 1)
|
|
self.assertEqual(s.step, None)
|
|
|
|
s = slice(1, 2)
|
|
self.assertEqual(s.start, 1)
|
|
self.assertEqual(s.stop, 2)
|
|
self.assertEqual(s.step, None)
|
|
|
|
s = slice(1, 2, 3)
|
|
self.assertEqual(s.start, 1)
|
|
self.assertEqual(s.stop, 2)
|
|
self.assertEqual(s.step, 3)
|
|
|
|
class AnyClass:
|
|
pass
|
|
|
|
obj = AnyClass()
|
|
s = slice(obj)
|
|
self.assertTrue(s.stop is obj)
|
|
|
|
def check_indices(self, slice, length):
|
|
try:
|
|
actual = slice.indices(length)
|
|
except ValueError:
|
|
actual = "valueerror"
|
|
try:
|
|
expected = slice_indices(slice, length)
|
|
except ValueError:
|
|
expected = "valueerror"
|
|
self.assertEqual(actual, expected)
|
|
|
|
if length >= 0 and slice.step != 0:
|
|
actual = range(*slice.indices(length))
|
|
expected = range(length)[slice]
|
|
self.assertEqual(actual, expected)
|
|
|
|
def test_indices(self):
|
|
self.assertEqual(slice(None ).indices(10), (0, 10, 1))
|
|
self.assertEqual(slice(None, None, 2).indices(10), (0, 10, 2))
|
|
self.assertEqual(slice(1, None, 2).indices(10), (1, 10, 2))
|
|
self.assertEqual(slice(None, None, -1).indices(10), (9, -1, -1))
|
|
self.assertEqual(slice(None, None, -2).indices(10), (9, -1, -2))
|
|
self.assertEqual(slice(3, None, -2).indices(10), (3, -1, -2))
|
|
# issue 3004 tests
|
|
self.assertEqual(slice(None, -9).indices(10), (0, 1, 1))
|
|
self.assertEqual(slice(None, -10).indices(10), (0, 0, 1))
|
|
self.assertEqual(slice(None, -11).indices(10), (0, 0, 1))
|
|
self.assertEqual(slice(None, -10, -1).indices(10), (9, 0, -1))
|
|
self.assertEqual(slice(None, -11, -1).indices(10), (9, -1, -1))
|
|
self.assertEqual(slice(None, -12, -1).indices(10), (9, -1, -1))
|
|
self.assertEqual(slice(None, 9).indices(10), (0, 9, 1))
|
|
self.assertEqual(slice(None, 10).indices(10), (0, 10, 1))
|
|
self.assertEqual(slice(None, 11).indices(10), (0, 10, 1))
|
|
self.assertEqual(slice(None, 8, -1).indices(10), (9, 8, -1))
|
|
self.assertEqual(slice(None, 9, -1).indices(10), (9, 9, -1))
|
|
self.assertEqual(slice(None, 10, -1).indices(10), (9, 9, -1))
|
|
|
|
self.assertEqual(
|
|
slice(-100, 100 ).indices(10),
|
|
slice(None).indices(10)
|
|
)
|
|
self.assertEqual(
|
|
slice(100, -100, -1).indices(10),
|
|
slice(None, None, -1).indices(10)
|
|
)
|
|
self.assertEqual(slice(-100, 100, 2).indices(10), (0, 10, 2))
|
|
|
|
self.assertEqual(list(range(10))[::sys.maxsize - 1], [0])
|
|
|
|
# Check a variety of start, stop, step and length values, including
|
|
# values exceeding sys.maxsize (see issue #14794).
|
|
vals = [None, -2**100, -2**30, -53, -7, -1, 0, 1, 7, 53, 2**30, 2**100]
|
|
lengths = [0, 1, 7, 53, 2**30, 2**100]
|
|
for slice_args in itertools.product(vals, repeat=3):
|
|
s = slice(*slice_args)
|
|
for length in lengths:
|
|
self.check_indices(s, length)
|
|
self.check_indices(slice(0, 10, 1), -3)
|
|
|
|
# Negative length should raise ValueError
|
|
with self.assertRaises(ValueError):
|
|
slice(None).indices(-1)
|
|
|
|
# Zero step should raise ValueError
|
|
with self.assertRaises(ValueError):
|
|
slice(0, 10, 0).indices(5)
|
|
|
|
# Using a start, stop or step or length that can't be interpreted as an
|
|
# integer should give a TypeError ...
|
|
with self.assertRaises(TypeError):
|
|
slice(0.0, 10, 1).indices(5)
|
|
with self.assertRaises(TypeError):
|
|
slice(0, 10.0, 1).indices(5)
|
|
with self.assertRaises(TypeError):
|
|
slice(0, 10, 1.0).indices(5)
|
|
with self.assertRaises(TypeError):
|
|
slice(0, 10, 1).indices(5.0)
|
|
|
|
# ... but it should be fine to use a custom class that provides index.
|
|
self.assertEqual(slice(0, 10, 1).indices(5), (0, 5, 1))
|
|
self.assertEqual(slice(MyIndexable(0), 10, 1).indices(5), (0, 5, 1))
|
|
self.assertEqual(slice(0, MyIndexable(10), 1).indices(5), (0, 5, 1))
|
|
self.assertEqual(slice(0, 10, MyIndexable(1)).indices(5), (0, 5, 1))
|
|
self.assertEqual(slice(0, 10, 1).indices(MyIndexable(5)), (0, 5, 1))
|
|
|
|
def test_setslice_without_getslice(self):
|
|
tmp = []
|
|
class X(object):
|
|
def __setitem__(self, i, k):
|
|
tmp.append((i, k))
|
|
|
|
x = X()
|
|
x[1:2] = 42
|
|
self.assertEqual(tmp, [(slice(1, 2), 42)])
|
|
|
|
def test_pickle(self):
|
|
s = slice(10, 20, 3)
|
|
for protocol in (0,1,2):
|
|
t = loads(dumps(s, protocol))
|
|
self.assertEqual(s, t)
|
|
self.assertEqual(s.indices(15), t.indices(15))
|
|
self.assertNotEqual(id(s), id(t))
|
|
|
|
def test_main():
|
|
support.run_unittest(SliceTest)
|
|
|
|
if __name__ == "__main__":
|
|
test_main()
|