test_bytes.py

"""Unit tests for the bytes and bytearray types.

XXX This is a mess.  Common tests should be unified with string_tests.py (and
the latter should be modernized).
"""

import array
import operator
import os
import re
import sys
import copy
import functools
import pickle
import tempfile
import textwrap
import threading
import unittest

import test.support
from test import support
from test.support import import_helper
from test.support import threading_helper
from test.support import warnings_helper
import test.string_tests
import test.list_tests
from test.support import bigaddrspacetest, MAX_Py_ssize_t
from test.support.script_helper import assert_python_failure


if sys.flags.bytes_warning:
    def check_bytes_warnings(func):
        @functools.wraps(func)
        def wrapper(*args, **kw):
            with warnings_helper.check_warnings(('', BytesWarning)):
                return func(*args, **kw)
        return wrapper
else:
    # no-op
    def check_bytes_warnings(func):
        return func


class Indexable:
    def __init__(self, value=0):
        self.value = value
    def __index__(self):
        return self.value


class BaseBytesTest:

    def assertTypedEqual(self, actual, expected):
        self.assertIs(type(actual), type(expected))
        self.assertEqual(actual, expected)

    def test_basics(self):
        b = self.type2test()
        self.assertEqual(type(b), self.type2test)
        self.assertEqual(b.__class__, self.type2test)

    def test_copy(self):
        a = self.type2test(b"abcd")
        for copy_method in (copy.copy, copy.deepcopy):
            b = copy_method(a)
            self.assertEqual(a, b)
            self.assertEqual(type(a), type(b))

    def test_empty_sequence(self):
        b = self.type2test()
        self.assertEqual(len(b), 0)
        self.assertRaises(IndexError, lambda: b[0])
        self.assertRaises(IndexError, lambda: b[1])
        self.assertRaises(IndexError, lambda: b[sys.maxsize])
        self.assertRaises(IndexError, lambda: b[sys.maxsize+1])
        self.assertRaises(IndexError, lambda: b[10**100])
        self.assertRaises(IndexError, lambda: b[-1])
        self.assertRaises(IndexError, lambda: b[-2])
        self.assertRaises(IndexError, lambda: b[-sys.maxsize])
        self.assertRaises(IndexError, lambda: b[-sys.maxsize-1])
        self.assertRaises(IndexError, lambda: b[-sys.maxsize-2])
        self.assertRaises(IndexError, lambda: b[-10**100])

    def test_from_iterable(self):
        b = self.type2test(range(256))
        self.assertEqual(len(b), 256)
        self.assertEqual(list(b), list(range(256)))

        # Non-sequence iterable.
        b = self.type2test({42})
        self.assertEqual(b, b"*")
        b = self.type2test({43, 45})
        self.assertIn(tuple(b), {(43, 45), (45, 43)})

        # Iterator that has a __length_hint__.
        b = self.type2test(iter(range(256)))
        self.assertEqual(len(b), 256)
        self.assertEqual(list(b), list(range(256)))

        # Iterator that doesn't have a __length_hint__.
        b = self.type2test(i for i in range(256) if i % 2)
        self.assertEqual(len(b), 128)
        self.assertEqual(list(b), list(range(256))[1::2])

        # Sequence without __iter__.
        class S:
            def __getitem__(self, i):
                return (1, 2, 3)[i]
        b = self.type2test(S())
        self.assertEqual(b, b"\x01\x02\x03")

    def test_from_tuple(self):
        # There is a special case for tuples.
        b = self.type2test(tuple(range(256)))
        self.assertEqual(len(b), 256)
        self.assertEqual(list(b), list(range(256)))
        b = self.type2test((1, 2, 3))
        self.assertEqual(b, b"\x01\x02\x03")

    def test_from_list(self):
        # There is a special case for lists.
        b = self.type2test(list(range(256)))
        self.assertEqual(len(b), 256)
        self.assertEqual(list(b), list(range(256)))
        b = self.type2test([1, 2, 3])
        self.assertEqual(b, b"\x01\x02\x03")

    def test_from_mutating_list(self):
        # Issue #34973: Crash in bytes constructor with mutating list.
        class X:
            def __index__(self):
                a.clear()
                return 42
        a = [X(), X()]
        self.assertEqual(bytes(a), b'*')

        class Y:
            def __index__(self):
                if len(a) < 1000:
                    a.append(self)
                return 42
        a = [Y()]
        self.assertEqual(bytes(a), b'*' * 1000)  # should not crash

    def test_from_index(self):
        b = self.type2test([Indexable(), Indexable(1), Indexable(254),
                            Indexable(255)])
        self.assertEqual(list(b), [0, 1, 254, 255])
        self.assertRaises(ValueError, self.type2test, [Indexable(-1)])
        self.assertRaises(ValueError, self.type2test, [Indexable(256)])

    def test_from_buffer(self):
        a = self.type2test(array.array('B', [1, 2, 3]))
        self.assertEqual(a, b"\x01\x02\x03")
        a = self.type2test(b"\x01\x02\x03")
        self.assertEqual(a, b"\x01\x02\x03")

        # Issues #29159 and #34974.
        # Fallback when __index__ raises a TypeError
        class B(bytes):
            def __index__(self):
                raise TypeError

        self.assertEqual(self.type2test(B(b"foobar")), b"foobar")

    def test_from_ssize(self):
        self.assertEqual(self.type2test(0), b'')
        self.assertEqual(self.type2test(1), b'\x00')
        self.assertEqual(self.type2test(5), b'\x00\x00\x00\x00\x00')
        self.assertRaises(ValueError, self.type2test, -1)

        self.assertEqual(self.type2test('0', 'ascii'), b'0')
        self.assertEqual(self.type2test(b'0'), b'0')
        self.assertRaises(OverflowError, self.type2test, sys.maxsize + 1)

    def test_constructor_type_errors(self):
        self.assertRaises(TypeError, self.type2test, 0.0)
        class C:
            pass
        self.assertRaises(TypeError, self.type2test, ["0"])
        self.assertRaises(TypeError, self.type2test, [0.0])
        self.assertRaises(TypeError, self.type2test, [None])
        self.assertRaises(TypeError, self.type2test, [C()])
        self.assertRaises(TypeError, self.type2test, encoding='ascii')
        self.assertRaises(TypeError, self.type2test, errors='ignore')
        self.assertRaises(TypeError, self.type2test, 0, 'ascii')
        self.assertRaises(TypeError, self.type2test, b'', 'ascii')
        self.assertRaises(TypeError, self.type2test, 0, errors='ignore')
        self.assertRaises(TypeError, self.type2test, b'', errors='ignore')
        self.assertRaises(TypeError, self.type2test, '')
        self.assertRaises(TypeError, self.type2test, '', errors='ignore')
        self.assertRaises(TypeError, self.type2test, '', b'ascii')
        self.assertRaises(TypeError, self.type2test, '', 'ascii', b'ignore')

    def test_constructor_value_errors(self):
        self.assertRaises(ValueError, self.type2test, [-1])
        self.assertRaises(ValueError, self.type2test, [-sys.maxsize])
        self.assertRaises(ValueError, self.type2test, [-sys.maxsize-1])
        self.assertRaises(ValueError, self.type2test, [-sys.maxsize-2])
        self.assertRaises(ValueError, self.type2test, [-10**100])
        self.assertRaises(ValueError, self.type2test, [256])
        self.assertRaises(ValueError, self.type2test, [257])
        self.assertRaises(ValueError, self.type2test, [sys.maxsize])
        self.assertRaises(ValueError, self.type2test, [sys.maxsize+1])
        self.assertRaises(ValueError, self.type2test, [10**100])

    @bigaddrspacetest
    def test_constructor_overflow(self):
        size = MAX_Py_ssize_t
        self.assertRaises((OverflowError, MemoryError), self.type2test, size)
        try:
            # Should either pass or raise an error (e.g. on debug builds with
            # additional malloc() overhead), but shouldn't crash.
            bytearray(size - 4)
        except (OverflowError, MemoryError):
            pass

    def test_constructor_exceptions(self):
        # Issue #34974: bytes and bytearray constructors replace unexpected
        # exceptions.
        class BadInt:
            def __index__(self):
                1/0
        self.assertRaises(ZeroDivisionError, self.type2test, BadInt())
        self.assertRaises(ZeroDivisionError, self.type2test, [BadInt()])

        class BadIterable:
            def __iter__(self):
                1/0
        self.assertRaises(ZeroDivisionError, self.type2test, BadIterable())

    def test_compare(self):
        b1 = self.type2test([1, 2, 3])
        b2 = self.type2test([1, 2, 3])
        b3 = self.type2test([1, 3])

        self.assertEqual(b1, b2)
        self.assertTrue(b2 != b3)
        self.assertTrue(b1 <= b2)
        self.assertTrue(b1 <= b3)
        self.assertTrue(b1 <  b3)
        self.assertTrue(b1 >= b2)
        self.assertTrue(b3 >= b2)
        self.assertTrue(b3 >  b2)

        self.assertFalse(b1 != b2)
        self.assertFalse(b2 == b3)
        self.assertFalse(b1 >  b2)
        self.assertFalse(b1 >  b3)
        self.assertFalse(b1 >= b3)
        self.assertFalse(b1 <  b2)
        self.assertFalse(b3 <  b2)
        self.assertFalse(b3 <= b2)

    @check_bytes_warnings
    def test_compare_to_str(self):
        # Byte comparisons with unicode should always fail!
        # Test this for all expected byte orders and Unicode character
        # sizes.
        self.assertEqual(self.type2test(b"\0a\0b\0c") == "abc", False)
        self.assertEqual(self.type2test(b"\0\0\0a\0\0\0b\0\0\0c") == "abc",
                            False)
        self.assertEqual(self.type2test(b"a\0b\0c\0") == "abc", False)
        self.assertEqual(self.type2test(b"a\0\0\0b\0\0\0c\0\0\0") == "abc",
                            False)
        self.assertEqual(self.type2test() == str(), False)
        self.assertEqual(self.type2test() != str(), True)

    def test_reversed(self):
        input = list(map(ord, "Hello"))
        b = self.type2test(input)
        output = list(reversed(b))
        input.reverse()
        self.assertEqual(output, input)

    def test_getslice(self):
        def by(s):
            return self.type2test(map(ord, s))
        b = by("Hello, world")

        self.assertEqual(b[:5], by("Hello"))
        self.assertEqual(b[1:5], by("ello"))
        self.assertEqual(b[5:7], by(", "))
        self.assertEqual(b[7:], by("world"))
        self.assertEqual(b[7:12], by("world"))
        self.assertEqual(b[7:100], by("world"))

        self.assertEqual(b[:-7], by("Hello"))
        self.assertEqual(b[-11:-7], by("ello"))
        self.assertEqual(b[-7:-5], by(", "))
        self.assertEqual(b[-5:], by("world"))
        self.assertEqual(b[-5:12], by("world"))
        self.assertEqual(b[-5:100], by("world"))
        self.assertEqual(b[-100:5], by("Hello"))

    def test_extended_getslice(self):
        # Test extended slicing by comparing with list slicing.
        L = list(range(255))
        b = self.type2test(L)
        indices = (0, None, 1, 3, 19, 100, sys.maxsize, -1, -2, -31, -100)
        for start in indices:
            for stop in indices:
                # Skip step 0 (invalid)
                for step in indices[1:]:
                    self.assertEqual(b[start:stop:step], self.type2test(L[start:stop:step]))

    def test_encoding(self):
        sample = "Hello world\n\u1234\u5678\u9abc"
        for enc in ("utf-8", "utf-16"):
            b = self.type2test(sample, enc)
            self.assertEqual(b, self.type2test(sample.encode(enc)))
        self.assertRaises(UnicodeEncodeError, self.type2test, sample, "latin-1")
        b = self.type2test(sample, "latin-1", "ignore")
        self.assertEqual(b, self.type2test(sample[:-3], "utf-8"))

    def test_decode(self):
        sample = "Hello world\n\u1234\u5678\u9abc"
        for enc in ("utf-8", "utf-16"):
            b = self.type2test(sample, enc)
            self.assertEqual(b.decode(enc), sample)
        sample = "Hello world\n\x80\x81\xfe\xff"
        b = self.type2test(sample, "latin-1")
        self.assertRaises(UnicodeDecodeError, b.decode, "utf-8")
        self.assertEqual(b.decode("utf-8", "ignore"), "Hello world\n")
        self.assertEqual(b.decode(errors="ignore", encoding="utf-8"),
                         "Hello world\n")
        # Default encoding is utf-8
        self.assertEqual(self.type2test(b'\xe2\x98\x83').decode(), '\u2603')

    def test_check_encoding_errors(self):
        # bpo-37388: bytes(str) and bytes.encode() must check encoding
        # and errors arguments in dev mode
        invalid = 'Boom, Shaka Laka, Boom!'
        encodings = ('ascii', 'utf8', 'latin1')
        code = textwrap.dedent(f'''
            import sys
            type2test = {self.type2test.__name__}
            encodings = {encodings!r}

            for data in ('', 'short string'):
                try:
                    type2test(data, encoding={invalid!r})
                except LookupError:
                    pass
                else:
                    sys.exit(21)

                for encoding in encodings:
                    try:
                        type2test(data, encoding=encoding, errors={invalid!r})
                    except LookupError:
                        pass
                    else:
                        sys.exit(22)

            for data in (b'', b'short string'):
                data = type2test(data)
                print(repr(data))
                try:
                    data.decode(encoding={invalid!r})
                except LookupError:
                    sys.exit(10)
                else:
                    sys.exit(23)

                try:
                    data.decode(errors={invalid!r})
                except LookupError:
                    pass
                else:
                    sys.exit(24)

                for encoding in encodings:
                    try:
                        data.decode(encoding=encoding, errors={invalid!r})
                    except LookupError:
                        pass
                    else:
                        sys.exit(25)

            sys.exit(10)
        ''')
        proc = assert_python_failure('-X', 'dev', '-c', code)
        self.assertEqual(proc.rc, 10, proc)

    def test_from_int(self):
        b = self.type2test(0)
        self.assertEqual(b, self.type2test())
        b = self.type2test(10)
        self.assertEqual(b, self.type2test([0]*10))
        b = self.type2test(10000)
        self.assertEqual(b, self.type2test([0]*10000))

    def test_concat(self):
        b1 = self.type2test(b"abc")
        b2 = self.type2test(b"def")
        self.assertEqual(b1 + b2, b"abcdef")
        self.assertEqual(b1 + bytes(b"def"), b"abcdef")
        self.assertEqual(bytes(b"def") + b1, b"defabc")
        self.assertRaises(TypeError, lambda: b1 + "def")
        self.assertRaises(TypeError, lambda: "abc" + b2)

    def test_repeat(self):
        for b in b"abc", self.type2test(b"abc"):
            self.assertEqual(b * 3, b"abcabcabc")
            self.assertEqual(b * 0, b"")
            self.assertEqual(b * -1, b"")
            self.assertRaises(TypeError, lambda: b * 3.14)
            self.assertRaises(TypeError, lambda: 3.14 * b)
            # XXX Shouldn't bytes and bytearray agree on what to raise?
            with self.assertRaises((OverflowError, MemoryError)):
                c = b * sys.maxsize
            with self.assertRaises((OverflowError, MemoryError)):
                b *= sys.maxsize

    def test_repeat_1char(self):
        self.assertEqual(self.type2test(b'x')*100, self.type2test([ord('x')]*100))

    def test_contains(self):
        b = self.type2test(b"abc")
        self.assertIn(ord('a'), b)
        self.assertIn(int(ord('a')), b)
        self.assertNotIn(200, b)
        self.assertRaises(ValueError, lambda: 300 in b)
        self.assertRaises(ValueError, lambda: -1 in b)
        self.assertRaises(ValueError, lambda: sys.maxsize+1 in b)
        self.assertRaises(TypeError, lambda: None in b)
        self.assertRaises(TypeError, lambda: float(ord('a')) in b)
        self.assertRaises(TypeError, lambda: "a" in b)
        for f in bytes, bytearray:
            self.assertIn(f(b""), b)
            self.assertIn(f(b"a"), b)
            self.assertIn(f(b"b"), b)
            self.assertIn(f(b"c"), b)
            self.assertIn(f(b"ab"), b)
            self.assertIn(f(b"bc"), b)
            self.assertIn(f(b"abc"), b)
            self.assertNotIn(f(b"ac"), b)
            self.assertNotIn(f(b"d"), b)
            self.assertNotIn(f(b"dab"), b)
            self.assertNotIn(f(b"abd"), b)

    def test_fromhex(self):
        self.assertRaises(TypeError, self.type2test.fromhex)
        self.assertRaises(TypeError, self.type2test.fromhex, 1)
        self.assertEqual(self.type2test.fromhex(''), self.type2test())
        b = bytearray([0x1a, 0x2b, 0x30])
        self.assertEqual(self.type2test.fromhex('1a2B30'), b)
        self.assertEqual(self.type2test.fromhex('  1A 2B  30   '), b)

        # check that ASCII whitespace is ignored
        self.assertEqual(self.type2test.fromhex(' 1A\n2B\t30\v'), b)
        self.assertEqual(self.type2test.fromhex(b' 1A\n2B\t30\v'), b)
        for c in "\x09\x0A\x0B\x0C\x0D\x20":
            self.assertEqual(self.type2test.fromhex(c), self.type2test())
        for c in "\x1C\x1D\x1E\x1F\x85\xa0\u2000\u2002\u2028":
            self.assertRaises(ValueError, self.type2test.fromhex, c)

        # Check that we can parse bytes and bytearray
        tests = [
            ("bytes", bytes),
            ("bytearray", bytearray),
            ("memoryview", memoryview),
            ("array.array", lambda bs: array.array('B', bs)),
        ]
        for name, factory in tests:
            with self.subTest(name=name):
                self.assertEqual(self.type2test.fromhex(factory(b' 1A 2B 30 ')), b)

        # Invalid bytes are rejected
        for u8 in b"\0\x1C\x1D\x1E\x1F\x85\xa0":
            b = bytes([30, 31, u8])
            self.assertRaises(ValueError, self.type2test.fromhex, b)

        self.assertEqual(self.type2test.fromhex('0000'), b'\0\0')
        with self.assertRaisesRegex(
            TypeError,
            r'fromhex\(\) argument must be str or bytes-like, not tuple',
        ):
            self.type2test.fromhex(())
        self.assertRaises(ValueError, self.type2test.fromhex, 'a')
        self.assertRaises(ValueError, self.type2test.fromhex, 'rt')
        self.assertRaises(ValueError, self.type2test.fromhex, '1a b cd')
        self.assertRaises(ValueError, self.type2test.fromhex, '\x00')
        self.assertRaises(ValueError, self.type2test.fromhex, '12   \x00   34')

        # For odd number of character(s)
        for value in ("a", "aaa", "deadbee"):
            with self.assertRaises(ValueError) as cm:
                self.type2test.fromhex(value)
            self.assertIn("fromhex() arg must contain an even number of hexadecimal digits", str(cm.exception))
        for value, position in (("a ", 1), (" aa a ", 5), (" aa a a ", 5)):
            with self.assertRaises(ValueError) as cm:
                self.type2test.fromhex(value)
            self.assertIn(f"non-hexadecimal number found in fromhex() arg at position {position}", str(cm.exception))

        for data, pos in (
            # invalid first hexadecimal character
            ('12 x4 56', 3),
            # invalid second hexadecimal character
            ('12 3x 56', 4),
            # two invalid hexadecimal characters
            ('12 xy 56', 3),
            # test non-ASCII string
            ('12 3\xff 56', 4),
        ):
            with self.assertRaises(ValueError) as cm:
                self.type2test.fromhex(data)
            self.assertIn('at position %s' % pos, str(cm.exception))

    def test_hex(self):
        self.assertRaises(TypeError, self.type2test.hex)
        self.assertRaises(TypeError, self.type2test.hex, 1)
        self.assertEqual(self.type2test(b"").hex(), "")
        self.assertEqual(bytearray([0x1a, 0x2b, 0x30]).hex(), '1a2b30')
        self.assertEqual(self.type2test(b"\x1a\x2b\x30").hex(), '1a2b30')
        self.assertEqual(memoryview(b"\x1a\x2b\x30").hex(), '1a2b30')

    def test_hex_separator_basics(self):
        three_bytes = self.type2test(b'\xb9\x01\xef')
        self.assertEqual(three_bytes.hex(), 'b901ef')
        with self.assertRaises(ValueError):
            three_bytes.hex('')
        with self.assertRaises(ValueError):
            three_bytes.hex('xx')
        self.assertEqual(three_bytes.hex(':', 0), 'b901ef')
        with self.assertRaises(TypeError):
            three_bytes.hex(None, 0)
        with self.assertRaises(ValueError):
            three_bytes.hex('\xff')
        with self.assertRaises(ValueError):
            three_bytes.hex(b'\xff')
        with self.assertRaises(ValueError):
            three_bytes.hex(b'\x80')
        with self.assertRaises(ValueError):
            three_bytes.hex(chr(0x100))
        self.assertEqual(three_bytes.hex(':', 0), 'b901ef')
        self.assertEqual(three_bytes.hex(b'\x00'), 'b9\x0001\x00ef')
        self.assertEqual(three_bytes.hex('\x00'), 'b9\x0001\x00ef')
        self.assertEqual(three_bytes.hex(b'\x7f'), 'b9\x7f01\x7fef')
        self.assertEqual(three_bytes.hex('\x7f'), 'b9\x7f01\x7fef')
        self.assertEqual(three_bytes.hex(':', 3), 'b901ef')
        self.assertEqual(three_bytes.hex(':', 4), 'b901ef')
        self.assertEqual(three_bytes.hex(':', -4), 'b901ef')
        self.assertEqual(three_bytes.hex(':'), 'b9:01:ef')
        self.assertEqual(three_bytes.hex(b'$'), 'b9$01$ef')
        self.assertEqual(three_bytes.hex(':', 1), 'b9:01:ef')
        self.assertEqual(three_bytes.hex(':', -1), 'b9:01:ef')
        self.assertEqual(three_bytes.hex(':', 2), 'b9:01ef')
        self.assertEqual(three_bytes.hex(':', 1), 'b9:01:ef')
        self.assertEqual(three_bytes.hex('*', -2), 'b901*ef')
        self.assertEqual(three_bytes.hex(sep=':', bytes_per_sep=2), 'b9:01ef')
        self.assertEqual(three_bytes.hex(sep='*', bytes_per_sep=-2), 'b901*ef')
        for bytes_per_sep in 3, -3, 2**31-1, -(2**31-1):
            with self.subTest(bytes_per_sep=bytes_per_sep):
                self.assertEqual(three_bytes.hex(':', bytes_per_sep), 'b901ef')
        for bytes_per_sep in 2**31, -2**31, 2**1000, -2**1000:
            with self.subTest(bytes_per_sep=bytes_per_sep):
                try:
                    self.assertEqual(three_bytes.hex(':', bytes_per_sep), 'b901ef')
                except OverflowError:
                    pass

        value = b'{s\005\000\000\000worldi\002\000\000\000s\005\000\000\000helloi\001\000\000\0000'
        self.assertEqual(value.hex('.', 8), '7b7305000000776f.726c646902000000.730500000068656c.6c6f690100000030')

    def test_hex_separator_five_bytes(self):
        five_bytes = self.type2test(range(90,95))
        self.assertEqual(five_bytes.hex(), '5a5b5c5d5e')

    def test_hex_separator_six_bytes(self):
        six_bytes = self.type2test(x*3 for x in range(1, 7))
        self.assertEqual(six_bytes.hex(), '0306090c0f12')
        self.assertEqual(six_bytes.hex('.', 1), '03.06.09.0c.0f.12')
        self.assertEqual(six_bytes.hex(' ', 2), '0306 090c 0f12')
        self.assertEqual(six_bytes.hex('-', 3), '030609-0c0f12')
        self.assertEqual(six_bytes.hex(':', 4), '0306:090c0f12')
        self.assertEqual(six_bytes.hex(':', 5), '03:06090c0f12')
        self.assertEqual(six_bytes.hex(':', 6), '0306090c0f12')
        self.assertEqual(six_bytes.hex(':', 95), '0306090c0f12')
        self.assertEqual(six_bytes.hex('_', -3), '030609_0c0f12')
        self.assertEqual(six_bytes.hex(':', -4), '0306090c:0f12')
        self.assertEqual(six_bytes.hex(b'@', -5), '0306090c0f@12')
        self.assertEqual(six_bytes.hex(':', -6), '0306090c0f12')
        self.assertEqual(six_bytes.hex(' ', -95), '0306090c0f12')

    def test_hex_simd_boundaries(self):
        # Test lengths around the SIMD threshold (16 bytes).
        # SIMD processes 16 bytes at a time; smaller inputs use scalar code.
        for length in (14, 15, 16, 17, 31, 32, 33, 64, 65):
            data = self.type2test(bytes(range(length)))
            expected = ''.join(f'{b:02x}' for b in range(length))
            with self.subTest(length=length):
                self.assertEqual(data.hex(), expected)

    def test_hex_nibble_boundaries(self):
        # Test the nibble value boundary at 9/10 (where '9' becomes 'a').
        # SIMD uses signed comparison for efficiency; verify correctness
        # at this boundary for various nibble combinations.
        boundary_bytes = self.type2test(bytes([
            0x09,  # both nibbles: 0, 9
            0x0a,  # both nibbles: 0, 10
            0x90,  # both nibbles: 9, 0
            0x99,  # both nibbles: 9, 9 (max all-digit)
            0x9a,  # both nibbles: 9, 10
            0xa0,  # both nibbles: 10, 0
            0xa9,  # both nibbles: 10, 9
            0xaa,  # both nibbles: 10, 10 (min all-letter)
            0x00,  # min value
            0xff,  # max value
        ]))
        self.assertEqual(boundary_bytes.hex(), '090a90999aa0a9aa00ff')

        # Repeat with 16+ bytes to exercise SIMD path
        simd_boundary = self.type2test(boundary_bytes * 2)
        self.assertEqual(simd_boundary.hex(), '090a90999aa0a9aa00ff' * 2)

    def test_join(self):
        self.assertEqual(self.type2test(b"").join([]), b"")
        self.assertEqual(self.type2test(b"").join([b""]), b"")
        for lst in [[b"abc"], [b"a", b"bc"], [b"ab", b"c"], [b"a", b"b", b"c"]]:
            lst = list(map(self.type2test, lst))
            self.assertEqual(self.type2test(b"").join(lst), b"abc")
            self.assertEqual(self.type2test(b"").join(tuple(lst)), b"abc")
            self.assertEqual(self.type2test(b"").join(iter(lst)), b"abc")
        dot_join = self.type2test(b".:").join
        self.assertEqual(dot_join([b"ab", b"cd"]), b"ab.:cd")
        self.assertEqual(dot_join([memoryview(b"ab"), b"cd"]), b"ab.:cd")
        self.assertEqual(dot_join([b"ab", memoryview(b"cd")]), b"ab.:cd")
        self.assertEqual(dot_join([bytearray(b"ab"), b"cd"]), b"ab.:cd")
        self.assertEqual(dot_join([b"ab", bytearray(b"cd")]), b"ab.:cd")
        # Stress it with many items
        seq = [b"abc"] * 100000
        expected = b"abc" + b".:abc" * 99999
        self.assertEqual(dot_join(seq), expected)
        # Stress test with empty separator
        seq = [b"abc"] * 100000
        expected = b"abc" * 100000
        self.assertEqual(self.type2test(b"").join(seq), expected)
        self.assertRaises(TypeError, self.type2test(b" ").join, None)
        # Error handling and cleanup when some item in the middle of the
        # sequence has the wrong type.
        with self.assertRaises(TypeError):
            dot_join([bytearray(b"ab"), "cd", b"ef"])
        with self.assertRaises(TypeError):
            dot_join([memoryview(b"ab"), "cd", b"ef"])

    def test_count(self):
        b = self.type2test(b'mississippi')
        i = 105
        p = 112
        w = 119

        self.assertEqual(b.count(b'i'), 4)
        self.assertEqual(b.count(b'ss'), 2)
        self.assertEqual(b.count(b'w'), 0)

        self.assertEqual(b.count(i), 4)
        self.assertEqual(b.count(w), 0)

        self.assertEqual(b.count(b'i', 6), 2)
        self.assertEqual(b.count(b'p', 6), 2)
        self.assertEqual(b.count(b'i', 1, 3), 1)
        self.assertEqual(b.count(b'p', 7, 9), 1)

        self.assertEqual(b.count(i, 6), 2)
        self.assertEqual(b.count(p, 6), 2)
        self.assertEqual(b.count(i, 1, 3), 1)
        self.assertEqual(b.count(p, 7, 9), 1)

    def test_startswith(self):
        b = self.type2test(b'hello')
        self.assertFalse(self.type2test().startswith(b"anything"))
        self.assertTrue(b.startswith(b"hello"))
        self.assertTrue(b.startswith(b"hel"))
        self.assertTrue(b.startswith(b"h"))
        self.assertFalse(b.startswith(b"hellow"))
        self.assertFalse(b.startswith(b"ha"))
        with self.assertRaises(TypeError) as cm:
            b.startswith([b'h'])
        exc = str(cm.exception)
        self.assertIn('bytes', exc)
        self.assertIn('tuple', exc)

    def test_endswith(self):
        b = self.type2test(b'hello')
        self.assertFalse(bytearray().endswith(b"anything"))
        self.assertTrue(b.endswith(b"hello"))
        self.assertTrue(b.endswith(b"llo"))
        self.assertTrue(b.endswith(b"o"))
        self.assertFalse(b.endswith(b"whello"))
        self.assertFalse(b.endswith(b"no"))
        with self.assertRaises(TypeError) as cm:
            b.endswith([b'o'])
        exc = str(cm.exception)
        self.assertIn('bytes', exc)
        self.assertIn('tuple', exc)

    def test_find(self):
        b = self.type2test(b'mississippi')
        i = 105
        w = 119

        self.assertEqual(b.find(b'ss'), 2)
        self.assertEqual(b.find(b'w'), -1)
        self.assertEqual(b.find(b'mississippian'), -1)

        self.assertEqual(b.find(i), 1)
        self.assertEqual(b.find(w), -1)

        self.assertEqual(b.find(b'ss', 3), 5)
        self.assertEqual(b.find(b'ss', 1, 7), 2)
        self.assertEqual(b.find(b'ss', 1, 3), -1)

        self.assertEqual(b.find(i, 6), 7)
        self.assertEqual(b.find(i, 1, 3), 1)
        self.assertEqual(b.find(w, 1, 3), -1)

        for index in (-1, 256, sys.maxsize + 1):
            self.assertRaisesRegex(
                ValueError, r'byte must be in range\(0, 256\)',
                b.find, index)

    def test_rfind(self):
        b = self.type2test(b'mississippi')
        i = 105
        w = 119

        self.assertEqual(b.rfind(b'ss'), 5)
        self.assertEqual(b.rfind(b'w'), -1)
        self.assertEqual(b.rfind(b'mississippian'), -1)

        self.assertEqual(b.rfind(i), 10)
        self.assertEqual(b.rfind(w), -1)

        self.assertEqual(b.rfind(b'ss', 3), 5)
        self.assertEqual(b.rfind(b'ss', 0, 6), 2)

        self.assertEqual(b.rfind(i, 1, 3), 1)
        self.assertEqual(b.rfind(i, 3, 9), 7)
        self.assertEqual(b.rfind(w, 1, 3), -1)

    def test_index(self):
        b = self.type2test(b'mississippi')
        i = 105
        w = 119

        self.assertEqual(b.index(b'ss'), 2)
        self.assertRaises(ValueError, b.index, b'w')
        self.assertRaises(ValueError, b.index, b'mississippian')

        self.assertEqual(b.index(i), 1)
        self.assertRaises(ValueError, b.index, w)

        self.assertEqual(b.index(b'ss', 3), 5)
        self.assertEqual(b.index(b'ss', 1, 7), 2)
        self.assertRaises(ValueError, b.index, b'ss', 1, 3)

        self.assertEqual(b.index(i, 6), 7)
        self.assertEqual(b.index(i, 1, 3), 1)
        self.assertRaises(ValueError, b.index, w, 1, 3)

    def test_rindex(self):
        b = self.type2test(b'mississippi')
        i = 105
        w = 119

        self.assertEqual(b.rindex(b'ss'), 5)
        self.assertRaises(ValueError, b.rindex, b'w')
        self.assertRaises(ValueError, b.rindex, b'mississippian')

        self.assertEqual(b.rindex(i), 10)
        self.assertRaises(ValueError, b.rindex, w)

        self.assertEqual(b.rindex(b'ss', 3), 5)
        self.assertEqual(b.rindex(b'ss', 0, 6), 2)

        self.assertEqual(b.rindex(i, 1, 3), 1)
        self.assertEqual(b.rindex(i, 3, 9), 7)
        self.assertRaises(ValueError, b.rindex, w, 1, 3)

    def test_mod(self):
        b = self.type2test(b'hello, %b!')
        orig = b
        b = b % b'world'
        self.assertEqual(b, b'hello, world!')
        self.assertEqual(orig, b'hello, %b!')
        self.assertFalse(b is orig)
        b = self.type2test(b'%s / 100 = %d%%')
        a = b % (b'seventy-nine', 79)
        self.assertEqual(a, b'seventy-nine / 100 = 79%')
        self.assertIs(type(a), self.type2test)
        # issue 29714
        b = self.type2test(b'hello,\x00%b!')
        b = b % b'world'
        self.assertEqual(b, b'hello,\x00world!')
        self.assertIs(type(b), self.type2test)

        def check(fmt, vals, result):
            b = self.type2test(fmt)
            b = b % vals
            self.assertEqual(b, result)
            self.assertIs(type(b), self.type2test)

        # A set of tests adapted from test_unicode:UnicodeTest.test_formatting
        check(b'...%(foo)b...', {b'foo':b"abc"}, b'...abc...')
        check(b'...%(f(o)o)b...', {b'f(o)o':b"abc", b'foo':b'bar'}, b'...abc...')
        check(b'...%(foo)b...', {b'foo':b"abc",b'def':123}, b'...abc...')
        check(b'%*b', (5, b'abc',), b'  abc')
        check(b'%*b', (-5, b'abc',), b'abc  ')
        check(b'%*.*b', (5, 2, b'abc',), b'   ab')
        check(b'%*.*b', (5, 3, b'abc',), b'  abc')
        check(b'%i %*.*b', (10, 5, 3, b'abc',), b'10   abc')
        check(b'%i%b %*.*b', (10, b'3', 5, 3, b'abc',), b'103   abc')
        check(b'%c', b'a', b'a')

        class PseudoFloat:
            def __init__(self, value):
                self.value = float(value)
            def __int__(self):
                return int(self.value)

        pi = PseudoFloat(3.1415)

        exceptions_params = [
            ('%x requires an integer, not float', b'%x', 3.14),
            ('%X requires an integer, not float', b'%X', 2.11),
            ('%o requires an integer, not float', b'%o', 1.79),
            (r'%x requires an integer, not .*\.PseudoFloat', b'%x', pi),
            ('%x requires an integer, not complex', b'%x', 3j),
            ('%X requires an integer, not complex', b'%X', 2j),
            ('%o requires an integer, not complex', b'%o', 1j),
            ('%u requires a real number, not complex', b'%u', 3j),
            ('%i requires a real number, not complex', b'%i', 2j),
            ('%d requires a real number, not complex', b'%d', 2j),
            (
                r'%c requires an integer in range\(256\)'
                r' or a single byte, not .*\.PseudoFloat',
                b'%c', pi
            ),
        ]

        for msg, format_bytes, value in exceptions_params:
            with self.assertRaisesRegex(TypeError, 'format argument: ' + msg):
                operator.mod(format_bytes, value)

    def test_memory_leak_gh_140939(self):
        # gh-140939: MemoryError is raised without leaking
        _testcapi = import_helper.import_module('_testcapi')
        with self.assertRaises(MemoryError):
            b = self.type2test(b'%*b')
            b % (_testcapi.PY_SSIZE_T_MAX, b'abc')

    def test_imod(self):
        b = self.type2test(b'hello, %b!')
        orig = b
        b %= b'world'
        self.assertEqual(b, b'hello, world!')
        self.assertEqual(orig, b'hello, %b!')
        self.assertFalse(b is orig)
        b = self.type2test(b'%s / 100 = %d%%')
        b %= (b'seventy-nine', 79)
        self.assertEqual(b, b'seventy-nine / 100 = 79%')
        self.assertIs(type(b), self.type2test)
        # issue 29714
        b = self.type2test(b'hello,\x00%b!')
        b %= b'world'
        self.assertEqual(b, b'hello,\x00world!')
        self.assertIs(type(b), self.type2test)

    def test_rmod(self):
        with self.assertRaises(TypeError):
            object() % self.type2test(b'abc')
        self.assertIs(self.type2test(b'abc').__rmod__('%r'), NotImplemented)

    def test_replace(self):
        b = self.type2test(b'mississippi')
        self.assertEqual(b.replace(b'i', b'a'), b'massassappa')
        self.assertEqual(b.replace(b'ss', b'x'), b'mixixippi')

    def test_replace_count_keyword(self):
        b = self.type2test(b'aa')
        self.assertEqual(b.replace(b'a', b'b', count=0), b'aa')
        self.assertEqual(b.replace(b'a', b'b', count=1), b'ba')
        self.assertEqual(b.replace(b'a', b'b', count=2), b'bb')
        self.assertEqual(b.replace(b'a', b'b', count=3), b'bb')

    def test_replace_int_error(self):
        self.assertRaises(TypeError, self.type2test(b'a b').replace, 32, b'')

    def test_split_string_error(self):
        self.assertRaises(TypeError, self.type2test(b'a b').split, ' ')
        self.assertRaises(TypeError, self.type2test(b'a b').rsplit, ' ')

    def test_split_int_error(self):
        self.assertRaises(TypeError, self.type2test(b'a b').split, 32)
        self.assertRaises(TypeError, self.type2test(b'a b').rsplit, 32)

    def test_split_unicodewhitespace(self):
        for b in (b'a\x1Cb', b'a\x1Db', b'a\x1Eb', b'a\x1Fb'):
            b = self.type2test(b)
            self.assertEqual(b.split(), [b])
        b = self.type2test(b"\x09\x0A\x0B\x0C\x0D\x1C\x1D\x1E\x1F")
        self.assertEqual(b.split(), [b'\x1c\x1d\x1e\x1f'])

    def test_rsplit_unicodewhitespace(self):
        b = self.type2test(b"\x09\x0A\x0B\x0C\x0D\x1C\x1D\x1E\x1F")
        self.assertEqual(b.rsplit(), [b'\x1c\x1d\x1e\x1f'])

    def test_partition(self):
        b = self.type2test(b'mississippi')
        self.assertEqual(b.partition(b'ss'), (b'mi', b'ss', b'issippi'))
        self.assertEqual(b.partition(b'w'), (b'mississippi', b'', b''))

    def test_rpartition(self):
        b = self.type2test(b'mississippi')
        self.assertEqual(b.rpartition(b'ss'), (b'missi', b'ss', b'ippi'))
        self.assertEqual(b.rpartition(b'i'), (b'mississipp', b'i', b''))
        self.assertEqual(b.rpartition(b'w'), (b'', b'', b'mississippi'))

    def test_partition_string_error(self):
        self.assertRaises(TypeError, self.type2test(b'a b').partition, ' ')
        self.assertRaises(TypeError, self.type2test(b'a b').rpartition, ' ')

    def test_partition_int_error(self):
        self.assertRaises(TypeError, self.type2test(b'a b').partition, 32)
        self.assertRaises(TypeError, self.type2test(b'a b').rpartition, 32)

    def test_pickling(self):
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            for b in b"", b"a", b"abc", b"\xffab\x80", b"\0\0\377\0\0":
                b = self.type2test(b)
                ps = pickle.dumps(b, proto)
                q = pickle.loads(ps)
                self.assertEqual(b, q)

    def test_iterator_pickling(self):
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            for b in b"", b"a", b"abc", b"\xffab\x80", b"\0\0\377\0\0":
                it = itorg = iter(self.type2test(b))
                data = list(self.type2test(b))
                d = pickle.dumps(it, proto)
                it = pickle.loads(d)
                self.assertEqual(type(itorg), type(it))
                self.assertEqual(list(it), data)

                it = pickle.loads(d)
                if not b:
                    continue
                next(it)
                d = pickle.dumps(it, proto)
                it = pickle.loads(d)
                self.assertEqual(list(it), data[1:])

    def test_strip_bytearray(self):
        self.assertEqual(self.type2test(b'abc').strip(memoryview(b'ac')), b'b')
        self.assertEqual(self.type2test(b'abc').lstrip(memoryview(b'ac')), b'bc')
        self.assertEqual(self.type2test(b'abc').rstrip(memoryview(b'ac')), b'ab')

    def test_strip_string_error(self):
        self.assertRaises(TypeError, self.type2test(b'abc').strip, 'ac')
        self.assertRaises(TypeError, self.type2test(b'abc').lstrip, 'ac')
        self.assertRaises(TypeError, self.type2test(b'abc').rstrip, 'ac')

    def test_strip_int_error(self):
        self.assertRaises(TypeError, self.type2test(b' abc ').strip, 32)
        self.assertRaises(TypeError, self.type2test(b' abc ').lstrip, 32)
        self.assertRaises(TypeError, self.type2test(b' abc ').rstrip, 32)

    def test_center(self):
        # Fill character can be either bytes or bytearray (issue 12380)
        b = self.type2test(b'abc')
        for fill_type in (bytes, bytearray):
            self.assertEqual(b.center(7, fill_type(b'-')),
                             self.type2test(b'--abc--'))

    def test_ljust(self):
        # Fill character can be either bytes or bytearray (issue 12380)
        b = self.type2test(b'abc')
        for fill_type in (bytes, bytearray):
            self.assertEqual(b.ljust(7, fill_type(b'-')),
                             self.type2test(b'abc----'))

    def test_rjust(self):
        # Fill character can be either bytes or bytearray (issue 12380)
        b = self.type2test(b'abc')
        for fill_type in (bytes, bytearray):
            self.assertEqual(b.rjust(7, fill_type(b'-')),
                             self.type2test(b'----abc'))

    def test_xjust_int_error(self):
        self.assertRaises(TypeError, self.type2test(b'abc').center, 7, 32)
        self.assertRaises(TypeError, self.type2test(b'abc').ljust, 7, 32)
        self.assertRaises(TypeError, self.type2test(b'abc').rjust, 7, 32)

    def test_ord(self):
        b = self.type2test(b'\0A\x7f\x80\xff')
        self.assertEqual([ord(b[i:i+1]) for i in range(len(b))],
                         [0, 65, 127, 128, 255])

    def test_maketrans(self):
        transtable = b'\000\001\002\003\004\005\006\007\010\011\012\013\014\015\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037 !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`xyzdefghijklmnopqrstuvwxyz{|}~\177\200\201\202\203\204\205\206\207\210\211\212\213\214\215\216\217\220\221\222\223\224\225\226\227\230\231\232\233\234\235\236\237\240\241\242\243\244\245\246\247\250\251\252\253\254\255\256\257\260\261\262\263\264\265\266\267\270\271\272\273\274\275\276\277\300\301\302\303\304\305\306\307\310\311\312\313\314\315\316\317\320\321\322\323\324\325\326\327\330\331\332\333\334\335\336\337\340\341\342\343\344\345\346\347\350\351\352\353\354\355\356\357\360\361\362\363\364\365\366\367\370\371\372\373\374\375\376\377'
        self.assertEqual(self.type2test.maketrans(b'abc', b'xyz'), transtable)
        transtable = b'\000\001\002\003\004\005\006\007\010\011\012\013\014\015\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037 !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\177\200\201\202\203\204\205\206\207\210\211\212\213\214\215\216\217\220\221\222\223\224\225\226\227\230\231\232\233\234\235\236\237\240\241\242\243\244\245\246\247\250\251\252\253\254\255\256\257\260\261\262\263\264\265\266\267\270\271\272\273\274\275\276\277\300\301\302\303\304\305\306\307\310\311\312\313\314\315\316\317\320\321\322\323\324\325\326\327\330\331\332\333\334\335\336\337\340\341\342\343\344\345\346\347\350\351\352\353\354\355\356\357\360\361\362\363\364\365\366\367\370\371\372\373\374xyz'
        self.assertEqual(self.type2test.maketrans(b'\375\376\377', b'xyz'), transtable)
        self.assertRaises(ValueError, self.type2test.maketrans, b'abc', b'xyzq')
        self.assertRaises(TypeError, self.type2test.maketrans, 'abc', 'def')

    def test_none_arguments(self):
        # issue 11828
        b = self.type2test(b'hello')
        l = self.type2test(b'l')
        h = self.type2test(b'h')
        x = self.type2test(b'x')
        o = self.type2test(b'o')

        self.assertEqual(2, b.find(l, None))
        self.assertEqual(3, b.find(l, -2, None))
        self.assertEqual(2, b.find(l, None, -2))
        self.assertEqual(0, b.find(h, None, None))

        self.assertEqual(3, b.rfind(l, None))
        self.assertEqual(3, b.rfind(l, -2, None))
        self.assertEqual(2, b.rfind(l, None, -2))
        self.assertEqual(0, b.rfind(h, None, None))

        self.assertEqual(2, b.index(l, None))
        self.assertEqual(3, b.index(l, -2, None))
        self.assertEqual(2, b.index(l, None, -2))
        self.assertEqual(0, b.index(h, None, None))

        self.assertEqual(3, b.rindex(l, None))
        self.assertEqual(3, b.rindex(l, -2, None))
        self.assertEqual(2, b.rindex(l, None, -2))
        self.assertEqual(0, b.rindex(h, None, None))

        self.assertEqual(2, b.count(l, None))
        self.assertEqual(1, b.count(l, -2, None))
        self.assertEqual(1, b.count(l, None, -2))
        self.assertEqual(0, b.count(x, None, None))

        self.assertEqual(True, b.endswith(o, None))
        self.assertEqual(True, b.endswith(o, -2, None))
        self.assertEqual(True, b.endswith(l, None, -2))
        self.assertEqual(False, b.endswith(x, None, None))

        self.assertEqual(True, b.startswith(h, None))
        self.assertEqual(True, b.startswith(l, -2, None))
        self.assertEqual(True, b.startswith(h, None, -2))
        self.assertEqual(False, b.startswith(x, None, None))

    def test_integer_arguments_out_of_byte_range(self):
        b = self.type2test(b'hello')

        for method in (b.count, b.find, b.index, b.rfind, b.rindex):
            self.assertRaises(ValueError, method, -1)
            self.assertRaises(ValueError, method, 256)
            self.assertRaises(ValueError, method, 9999)

    def test_find_etc_raise_correct_error_messages(self):
        # issue 11828
        b = self.type2test(b'hello')
        x = self.type2test(b'x')
        self.assertRaisesRegex(TypeError, r'\bfind\b', b.find,
                                x, None, None, None)
        self.assertRaisesRegex(TypeError, r'\brfind\b', b.rfind,
                                x, None, None, None)
        self.assertRaisesRegex(TypeError, r'\bindex\b', b.index,
                                x, None, None, None)
        self.assertRaisesRegex(TypeError, r'\brindex\b', b.rindex,
                                x, None, None, None)
        self.assertRaisesRegex(TypeError, r'\bcount\b', b.count,
                                x, None, None, None)
        self.assertRaisesRegex(TypeError, r'\bstartswith\b', b.startswith,
                                x, None, None, None)
        self.assertRaisesRegex(TypeError, r'\bendswith\b', b.endswith,
                                x, None, None, None)

    def test_free_after_iterating(self):
        test.support.check_free_after_iterating(self, iter, self.type2test)
        test.support.check_free_after_iterating(self, reversed, self.type2test)

    def test_translate(self):
        b = self.type2test(b'hello')
        rosetta = bytearray(range(256))
        rosetta[ord('o')] = ord('e')

        self.assertRaises(TypeError, b.translate)
        self.assertRaises(TypeError, b.translate, None, None)
        self.assertRaises(ValueError, b.translate, bytes(range(255)))

        c = b.translate(rosetta, b'hello')
        self.assertEqual(b, b'hello')
        self.assertIsInstance(c, self.type2test)

        c = b.translate(rosetta)
        d = b.translate(rosetta, b'')
        self.assertEqual(c, d)
        self.assertEqual(c, b'helle')

        c = b.translate(rosetta, b'l')
        self.assertEqual(c, b'hee')
        c = b.translate(None, b'e')
        self.assertEqual(c, b'hllo')

        # test delete as a keyword argument
        c = b.translate(rosetta, delete=b'')
        self.assertEqual(c, b'helle')
        c = b.translate(rosetta, delete=b'l')
        self.assertEqual(c, b'hee')
        c = b.translate(None, delete=b'e')
        self.assertEqual(c, b'hllo')

    def test_sq_item(self):
        _testlimitedcapi = import_helper.import_module('_testlimitedcapi')
        obj = self.type2test((42,))
        with self.assertRaises(IndexError):
            _testlimitedcapi.sequence_getitem(obj, -2)
        with self.assertRaises(IndexError):
            _testlimitedcapi.sequence_getitem(obj, 1)
        self.assertEqual(_testlimitedcapi.sequence_getitem(obj, 0), 42)


class BytesTest(BaseBytesTest, unittest.TestCase):
    type2test = bytes

    def test__bytes__(self):
        foo = b'foo\x00bar'
        self.assertEqual(foo.__bytes__(), foo)
        self.assertEqual(type(foo.__bytes__()), self.type2test)

        class bytes_subclass(bytes):
            pass

        bar = bytes_subclass(b'bar\x00foo')
        self.assertEqual(bar.__bytes__(), bar)
        self.assertEqual(type(bar.__bytes__()), self.type2test)

    def test_getitem_error(self):
        b = b'python'
        msg = "byte indices must be integers or slices"
        with self.assertRaisesRegex(TypeError, msg):
            b['a']

    def test_buffer_is_readonly(self):
        fd = os.open(__file__, os.O_RDONLY)
        with open(fd, "rb", buffering=0) as f:
            self.assertRaises(TypeError, f.readinto, b"")

    def test_custom(self):
        self.assertEqual(bytes(BytesSubclass(b'abc')), b'abc')
        self.assertEqual(BytesSubclass(OtherBytesSubclass(b'abc')),
                         BytesSubclass(b'abc'))
        self.assertEqual(bytes(WithBytes(b'abc')), b'abc')
        self.assertEqual(BytesSubclass(WithBytes(b'abc')), BytesSubclass(b'abc'))

        class NoBytes: pass
        self.assertRaises(TypeError, bytes, NoBytes())
        self.assertRaises(TypeError, bytes, WithBytes('abc'))
        self.assertRaises(TypeError, bytes, WithBytes(None))
        class IndexWithBytes:
            def __bytes__(self):
                return b'a'
            def __index__(self):
                return 42
        self.assertEqual(bytes(IndexWithBytes()), b'a')
        # Issue #25766
        class StrWithBytes(str):
            def __new__(cls, value):
                self = str.__new__(cls, '\u20ac')
                self.value = value
                return self
            def __bytes__(self):
                return self.value
        self.assertEqual(bytes(StrWithBytes(b'abc')), b'abc')
        self.assertEqual(bytes(StrWithBytes(b'abc'), 'iso8859-15'), b'\xa4')
        self.assertEqual(bytes(StrWithBytes(BytesSubclass(b'abc'))), b'abc')
        self.assertEqual(BytesSubclass(StrWithBytes(b'abc')), BytesSubclass(b'abc'))
        self.assertEqual(BytesSubclass(StrWithBytes(b'abc'), 'iso8859-15'),
                         BytesSubclass(b'\xa4'))
        self.assertEqual(BytesSubclass(StrWithBytes(BytesSubclass(b'abc'))),
                         BytesSubclass(b'abc'))
        self.assertEqual(BytesSubclass(StrWithBytes(OtherBytesSubclass(b'abc'))),
                         BytesSubclass(b'abc'))
        # Issue #24731
        self.assertTypedEqual(bytes(WithBytes(BytesSubclass(b'abc'))), BytesSubclass(b'abc'))
        self.assertTypedEqual(BytesSubclass(WithBytes(BytesSubclass(b'abc'))),
                              BytesSubclass(b'abc'))
        self.assertTypedEqual(BytesSubclass(WithBytes(OtherBytesSubclass(b'abc'))),
                              BytesSubclass(b'abc'))

        class BytesWithBytes(bytes):
            def __new__(cls, value):
                self = bytes.__new__(cls, b'\xa4')
                self.value = value
                return self
            def __bytes__(self):
                return self.value
        self.assertTypedEqual(bytes(BytesWithBytes(b'abc')), b'abc')
        self.assertTypedEqual(BytesSubclass(BytesWithBytes(b'abc')),
                              BytesSubclass(b'abc'))
        self.assertTypedEqual(bytes(BytesWithBytes(BytesSubclass(b'abc'))),
                              BytesSubclass(b'abc'))
        self.assertTypedEqual(BytesSubclass(BytesWithBytes(BytesSubclass(b'abc'))),
                              BytesSubclass(b'abc'))
        self.assertTypedEqual(BytesSubclass(BytesWithBytes(OtherBytesSubclass(b'abc'))),
                              BytesSubclass(b'abc'))

    # Test PyBytes_FromFormat()
    def test_from_format(self):
        ctypes = import_helper.import_module('ctypes')
        _testcapi = import_helper.import_module('_testcapi')
        from ctypes import pythonapi, py_object
        from ctypes import (
            c_int, c_uint,
            c_long, c_ulong,
            c_size_t, c_ssize_t,
            c_char_p)

        PyBytes_FromFormat = pythonapi.PyBytes_FromFormat
        PyBytes_FromFormat.argtypes = (c_char_p,)
        PyBytes_FromFormat.restype = py_object

        # basic tests
        self.assertEqual(PyBytes_FromFormat(b'format'),
                         b'format')
        self.assertEqual(PyBytes_FromFormat(b'Hello %s !', b'world'),
                         b'Hello world !')

        # test formatters
        self.assertEqual(PyBytes_FromFormat(b'c=%c', c_int(0)),
                         b'c=\0')
        self.assertEqual(PyBytes_FromFormat(b'c=%c', c_int(ord('@'))),
                         b'c=@')
        self.assertEqual(PyBytes_FromFormat(b'c=%c', c_int(255)),
                         b'c=\xff')
        self.assertEqual(PyBytes_FromFormat(b'd=%d ld=%ld zd=%zd',
                                            c_int(1), c_long(2),
                                            c_size_t(3)),
                         b'd=1 ld=2 zd=3')
        self.assertEqual(PyBytes_FromFormat(b'd=%d ld=%ld zd=%zd',
                                            c_int(-1), c_long(-2),
                                            c_size_t(-3)),
                         b'd=-1 ld=-2 zd=-3')
        self.assertEqual(PyBytes_FromFormat(b'u=%u lu=%lu zu=%zu',
                                            c_uint(123), c_ulong(456),
                                            c_size_t(789)),
                         b'u=123 lu=456 zu=789')
        self.assertEqual(PyBytes_FromFormat(b'i=%i', c_int(123)),
                         b'i=123')
        self.assertEqual(PyBytes_FromFormat(b'i=%i', c_int(-123)),
                         b'i=-123')
        self.assertEqual(PyBytes_FromFormat(b'x=%x', c_int(0xabc)),
                         b'x=abc')

        sizeof_ptr = ctypes.sizeof(c_char_p)

        if os.name == 'nt':
            # Windows (MSCRT)
            ptr_format = '0x%0{}X'.format(2 * sizeof_ptr)
            def ptr_formatter(ptr):
                return (ptr_format % ptr)
        else:
            # UNIX (glibc)
            def ptr_formatter(ptr):
                return '%#x' % ptr

        ptr = 0xabcdef
        self.assertEqual(PyBytes_FromFormat(b'ptr=%p', c_char_p(ptr)),
                         ('ptr=' + ptr_formatter(ptr)).encode('ascii'))
        self.assertEqual(PyBytes_FromFormat(b's=%s', c_char_p(b'cstr')),
                         b's=cstr')

        # test minimum and maximum integer values
        size_max = c_size_t(-1).value
        for formatstr, ctypes_type, value, py_formatter in (
            (b'%d', c_int, _testcapi.INT_MIN, str),
            (b'%d', c_int, _testcapi.INT_MAX, str),
            (b'%ld', c_long, _testcapi.LONG_MIN, str),
            (b'%ld', c_long, _testcapi.LONG_MAX, str),
            (b'%lu', c_ulong, _testcapi.ULONG_MAX, str),
            (b'%zd', c_ssize_t, _testcapi.PY_SSIZE_T_MIN, str),
            (b'%zd', c_ssize_t, _testcapi.PY_SSIZE_T_MAX, str),
            (b'%zu', c_size_t, size_max, str),
            (b'%p', c_char_p, size_max, ptr_formatter),
        ):
            self.assertEqual(PyBytes_FromFormat(formatstr, ctypes_type(value)),
                             py_formatter(value).encode('ascii')),

        # width and precision (width is currently ignored)
        self.assertEqual(PyBytes_FromFormat(b'%5s', b'a'),
                         b'a')
        self.assertEqual(PyBytes_FromFormat(b'%.3s', b'abcdef'),
                         b'abc')

        # '%%' formatter
        self.assertEqual(PyBytes_FromFormat(b'%%'),
                         b'%')
        self.assertEqual(PyBytes_FromFormat(b'[%%]'),
                         b'[%]')
        self.assertEqual(PyBytes_FromFormat(b'%%%c', c_int(ord('_'))),
                         b'%_')
        self.assertEqual(PyBytes_FromFormat(b'%%s'),
                         b'%s')

        # Invalid formats and partial formatting
        self.assertEqual(PyBytes_FromFormat(b'%'), b'%')
        self.assertEqual(PyBytes_FromFormat(b'x=%i y=%', c_int(2), c_int(3)),
                         b'x=2 y=%')

        # Issue #19969: %c must raise OverflowError for values
        # not in the range [0; 255]
        self.assertRaises(OverflowError,
                          PyBytes_FromFormat, b'%c', c_int(-1))
        self.assertRaises(OverflowError,
                          PyBytes_FromFormat, b'%c', c_int(256))

        # Issue #33817: empty strings
        self.assertEqual(PyBytes_FromFormat(b''),
                         b'')
        self.assertEqual(PyBytes_FromFormat(b'%s', b''),
                         b'')

    def test_bytes_blocking(self):
        class IterationBlocked(list):
            __bytes__ = None
        i = [0, 1, 2, 3]
        self.assertEqual(bytes(i), b'\x00\x01\x02\x03')
        self.assertRaises(TypeError, bytes, IterationBlocked(i))

        # At least in CPython, because bytes.__new__ and the C API
        # PyBytes_FromObject have different fallback rules, integer
        # fallback is handled specially, so test separately.
        class IntBlocked(int):
            __bytes__ = None
        self.assertEqual(bytes(3), b'\0\0\0')
        self.assertRaises(TypeError, bytes, IntBlocked(3))

        # While there is no separately-defined rule for handling bytes
        # subclasses differently from other buffer-interface classes,
        # an implementation may well special-case them (as CPython 2.x
        # str did), so test them separately.
        class BytesSubclassBlocked(bytes):
            __bytes__ = None
        self.assertEqual(bytes(b'ab'), b'ab')
        self.assertRaises(TypeError, bytes, BytesSubclassBlocked(b'ab'))

        class BufferBlocked(bytearray):
            __bytes__ = None
        ba, bb = bytearray(b'ab'), BufferBlocked(b'ab')
        self.assertEqual(bytes(ba), b'ab')
        self.assertRaises(TypeError, bytes, bb)

    def test_repeat_id_preserving(self):
        a = b'123abc1@'
        b = b'456zyx-+'
        self.assertEqual(id(a), id(a))
        self.assertNotEqual(id(a), id(b))
        self.assertNotEqual(id(a), id(a * -4))
        self.assertNotEqual(id(a), id(a * 0))
        self.assertEqual(id(a), id(a * 1))
        self.assertEqual(id(a), id(1 * a))
        self.assertNotEqual(id(a), id(a * 2))

        class SubBytes(bytes):
            pass

        s = SubBytes(b'qwerty()')
        self.assertEqual(id(s), id(s))
        self.assertNotEqual(id(s), id(s * -4))
        self.assertNotEqual(id(s), id(s * 0))
        self.assertNotEqual(id(s), id(s * 1))
        self.assertNotEqual(id(s), id(1 * s))
        self.assertNotEqual(id(s), id(s * 2))


class ByteArrayTest(BaseBytesTest, unittest.TestCase):
    type2test = bytearray

    _testlimitedcapi = import_helper.import_module('_testlimitedcapi')

    def test_getitem_error(self):
        b = bytearray(b'python')
        msg = "bytearray indices must be integers or slices"
        with self.assertRaisesRegex(TypeError, msg):
            b['a']

    def test_setitem_error(self):
        b = bytearray(b'python')
        msg = "bytearray indices must be integers or slices"
        with self.assertRaisesRegex(TypeError, msg):
            b['a'] = "python"

    def test_nohash(self):
        self.assertRaises(TypeError, hash, bytearray())

    def test_bytearray_api(self):
        short_sample = b"Hello world\n"
        sample = short_sample + b"\0"*(20 - len(short_sample))
        tfn = tempfile.mktemp()
        try:
            # Prepare
            with open(tfn, "wb") as f:
                f.write(short_sample)
            # Test readinto
            with open(tfn, "rb") as f:
                b = bytearray(20)
                n = f.readinto(b)
            self.assertEqual(n, len(short_sample))
            self.assertEqual(list(b), list(sample))
            # Test writing in binary mode
            with open(tfn, "wb") as f:
                f.write(b)
            with open(tfn, "rb") as f:
                self.assertEqual(f.read(), sample)
            # Text mode is ambiguous; don't test
        finally:
            try:
                os.remove(tfn)
            except OSError:
                pass

    def test_mod_concurrent_mutation(self):
        # Prevent crash in __mod__ when formatting mutates the bytearray.
        # Regression test for https://github.com/python/cpython/issues/142557.
        fmt = bytearray(b"%a end")

        class S:
            def __repr__(self):
                fmt.clear()
                return "E"

        self.assertRaises(BufferError, fmt.__mod__, S())

    def test_reverse(self):
        b = bytearray(b'hello')
        self.assertEqual(b.reverse(), None)
        self.assertEqual(b, b'olleh')
        b = bytearray(b'hello1') # test even number of items
        b.reverse()
        self.assertEqual(b, b'1olleh')
        b = bytearray()
        b.reverse()
        self.assertFalse(b)

    def test_clear(self):
        b = bytearray(b'python')
        b.clear()
        self.assertEqual(b, b'')

        b = bytearray(b'')
        b.clear()
        self.assertEqual(b, b'')

        b = bytearray(b'')
        b.append(ord('r'))
        b.clear()
        b.append(ord('p'))
        self.assertEqual(b, b'p')

        # Cleared object should be empty.
        b = bytearray(b'abc')
        b.clear()
        self.assertEqual(b.__alloc__(), 0)
        base_size = sys.getsizeof(bytearray())
        self.assertEqual(sys.getsizeof(b), base_size)
        c = b.copy()
        self.assertEqual(c.__alloc__(), 0)
        self.assertEqual(sys.getsizeof(c), base_size)

    def test_copy(self):
        b = bytearray(b'abc')
        bb = b.copy()
        self.assertEqual(bb, b'abc')

        b = bytearray(b'')
        bb = b.copy()
        self.assertEqual(bb, b'')

        # test that it's indeed a copy and not a reference
        b = bytearray(b'abc')
        bb = b.copy()
        self.assertEqual(b, bb)
        self.assertIsNot(b, bb)
        bb.append(ord('d'))
        self.assertEqual(bb, b'abcd')
        self.assertEqual(b, b'abc')

    def test_regexps(self):
        def by(s):
            return bytearray(map(ord, s))
        b = by("Hello, world")
        self.assertEqual(re.findall(br"\w+", b), [by("Hello"), by("world")])

    def test_resize(self):
        ba = bytearray(b'abcdef')
        self.assertIsNone(ba.resize(3))
        self.assertEqual(ba, bytearray(b'abc'))

        self.assertIsNone(ba.resize(10))
        self.assertEqual(len(ba), 10)
        # Bytes beyond set values must be cleared.
        self.assertEqual(ba, bytearray(b'abc\0\0\0\0\0\0\0'))

        ba[3:10] = b'defghij'
        self.assertEqual(ba, bytearray(b'abcdefghij'))

        self.assertIsNone(ba.resize(2 ** 20))
        self.assertEqual(len(ba), 2**20)
        self.assertEqual(ba, bytearray(b'abcdefghij' + b'\0' * (2 ** 20 - 10)))

        self.assertIsNone(ba.resize(0))
        self.assertEqual(ba, bytearray())

        self.assertIsNone(ba.resize(10))
        self.assertEqual(ba, bytearray(b'\0' * 10))

        # Subclass
        ba = ByteArraySubclass(b'abcdef')
        self.assertIsNone(ba.resize(3))
        self.assertEqual(ba, bytearray(b'abc'))

        # Check arguments
        self.assertRaises(TypeError, bytearray().resize)
        self.assertRaises(TypeError, bytearray().resize, (10, 10))

        self.assertRaises(ValueError, bytearray().resize, -1)
        self.assertRaises(ValueError, bytearray().resize, -200)
        self.assertRaises(MemoryError, bytearray().resize, sys.maxsize)
        self.assertRaises(MemoryError, bytearray(1000).resize, sys.maxsize)

    def test_take_bytes(self):
        ba = bytearray(b'ab')
        self.assertEqual(ba.take_bytes(), b'ab')
        self.assertEqual(len(ba), 0)
        self.assertEqual(ba, bytearray(b''))
        self.assertEqual(ba.__alloc__(), 0)
        base_size = sys.getsizeof(bytearray())
        self.assertEqual(sys.getsizeof(ba), base_size)

        # Positive and negative slicing.
        ba = bytearray(b'abcdef')
        self.assertEqual(ba.take_bytes(1), b'a')
        self.assertEqual(ba, bytearray(b'bcdef'))
        self.assertEqual(len(ba), 5)
        self.assertEqual(ba.take_bytes(-5), b'')
        self.assertEqual(ba, bytearray(b'bcdef'))
        self.assertEqual(len(ba), 5)
        self.assertEqual(ba.take_bytes(-3), b'bc')
        self.assertEqual(ba, bytearray(b'def'))
        self.assertEqual(len(ba), 3)
        self.assertEqual(ba.take_bytes(3), b'def')
        self.assertEqual(ba, bytearray(b''))
        self.assertEqual(len(ba), 0)

        # Take nothing from emptiness.
        self.assertEqual(ba.take_bytes(0), b'')
        self.assertEqual(ba.take_bytes(), b'')
        self.assertEqual(ba.take_bytes(None), b'')

        # Out of bounds, bad take value.
        self.assertRaises(IndexError, ba.take_bytes, -1)
        self.assertRaises(TypeError, ba.take_bytes, 3.14)
        ba = bytearray(b'abcdef')
        self.assertRaises(IndexError, ba.take_bytes, 7)

        # Offset between physical and logical start (ob_bytes != ob_start).
        ba = bytearray(b'abcde')
        del ba[:2]
        self.assertEqual(ba, bytearray(b'cde'))
        self.assertEqual(ba.take_bytes(), b'cde')

        # Overallocation at end.
        ba = bytearray(b'abcde')
        del ba[-2:]
        self.assertEqual(ba, bytearray(b'abc'))
        self.assertEqual(ba.take_bytes(), b'abc')
        ba = bytearray(b'abcde')
        ba.resize(4)
        self.assertEqual(ba.take_bytes(), b'abcd')

        # Take of a bytearray with references should fail.
        ba = bytearray(b'abc')
        with memoryview(ba) as mv:
            self.assertRaises(BufferError, ba.take_bytes)
        self.assertEqual(ba.take_bytes(), b'abc')

    @support.cpython_only  # tests an implementation detail
    def test_take_bytes_optimization(self):
        # Validate optimization around taking lots of little chunks out of a
        # much bigger buffer. Save work by only copying a little rather than
        # moving a lot.
        ba = bytearray(b'abcdef' + b'0' * 1000)
        start_alloc = ba.__alloc__()

        # Take two bytes at a time, checking alloc doesn't change.
        self.assertEqual(ba.take_bytes(2), b'ab')
        self.assertEqual(ba.__alloc__(), start_alloc)
        self.assertEqual(len(ba), 4 + 1000)
        self.assertEqual(ba.take_bytes(2), b'cd')
        self.assertEqual(ba.__alloc__(), start_alloc)
        self.assertEqual(len(ba), 2 + 1000)
        self.assertEqual(ba.take_bytes(2), b'ef')
        self.assertEqual(ba.__alloc__(), start_alloc)
        self.assertEqual(len(ba), 0 + 1000)
        self.assertEqual(ba.__alloc__(), start_alloc)

        # Take over half, alloc shrinks to exact size.
        self.assertEqual(ba.take_bytes(501), b'0' * 501)
        self.assertEqual(len(ba), 499)
        bytes_header_size = sys.getsizeof(b'')
        self.assertEqual(ba.__alloc__(), 499 + bytes_header_size)

    def test_setitem(self):
        def setitem_as_mapping(b, i, val):
            b[i] = val

        def setitem_as_sequence(b, i, val):
            self._testlimitedcapi.sequence_setitem(b, i, val)

        def do_tests(setitem):
            b = bytearray([1, 2, 3])
            setitem(b, 1, 100)
            self.assertEqual(b, bytearray([1, 100, 3]))
            setitem(b, -1, 200)
            self.assertEqual(b, bytearray([1, 100, 200]))
            setitem(b, 0, Indexable(10))
            self.assertEqual(b, bytearray([10, 100, 200]))
            try:
                setitem(b, 3, 0)
                self.fail("Didn't raise IndexError")
            except IndexError:
                pass
            try:
                setitem(b, -10, 0)
                self.fail("Didn't raise IndexError")
            except IndexError:
                pass
            try:
                setitem(b, 0, 256)
                self.fail("Didn't raise ValueError")
            except ValueError:
                pass
            try:
                setitem(b, 0, Indexable(-1))
                self.fail("Didn't raise ValueError")
            except ValueError:
                pass
            try:
                setitem(b, 0, object())
                self.fail("Didn't raise TypeError")
            except TypeError:
                pass

        with self.subTest("tp_as_mapping"):
            do_tests(setitem_as_mapping)

        with self.subTest("tp_as_sequence"):
            do_tests(setitem_as_sequence)

    def test_delitem(self):
        def del_as_mapping(b, i):
            del b[i]

        def del_as_sequence(b, i):
            self._testlimitedcapi.sequence_delitem(b, i)

        def do_tests(delete):
            b = bytearray(range(10))
            delete(b, 0)
            self.assertEqual(b, bytearray(range(1, 10)))
            delete(b, -1)
            self.assertEqual(b, bytearray(range(1, 9)))
            delete(b, 4)
            self.assertEqual(b, bytearray([1, 2, 3, 4, 6, 7, 8]))

        with self.subTest("tp_as_mapping"):
            do_tests(del_as_mapping)

        with self.subTest("tp_as_sequence"):
            do_tests(del_as_sequence)

    def test_setslice(self):
        b = bytearray(range(10))
        self.assertEqual(list(b), list(range(10)))

        b[0:5] = bytearray([1, 1, 1, 1, 1])
        self.assertEqual(b, bytearray([1, 1, 1, 1, 1, 5, 6, 7, 8, 9]))

        del b[0:-5]
        self.assertEqual(b, bytearray([5, 6, 7, 8, 9]))

        b[0:0] = bytearray([0, 1, 2, 3, 4])
        self.assertEqual(b, bytearray(range(10)))

        b[-7:-3] = bytearray([100, 101])
        self.assertEqual(b, bytearray([0, 1, 2, 100, 101, 7, 8, 9]))

        b[3:5] = [3, 4, 5, 6]
        self.assertEqual(b, bytearray(range(10)))

        b[3:0] = [42, 42, 42]
        self.assertEqual(b, bytearray([0, 1, 2, 42, 42, 42, 3, 4, 5, 6, 7, 8, 9]))

        b[3:] = b'foo'
        self.assertEqual(b, bytearray([0, 1, 2, 102, 111, 111]))

        b[:3] = memoryview(b'foo')
        self.assertEqual(b, bytearray([102, 111, 111, 102, 111, 111]))

        b[3:4] = []
        self.assertEqual(b, bytearray([102, 111, 111, 111, 111]))

        for elem in [5, -5, 0, int(10e20), 'str', 2.3,
                     ['a', 'b'], [b'a', b'b'], [[]]]:
            with self.assertRaises(TypeError):
                b[3:4] = elem

        for elem in [[254, 255, 256], [-256, 9000]]:
            with self.assertRaises(ValueError):
                b[3:4] = elem

    def test_setslice_extend(self):
        # Exercise the resizing logic (see issue #19087)
        b = bytearray(range(100))
        self.assertEqual(list(b), list(range(100)))
        del b[:10]
        self.assertEqual(list(b), list(range(10, 100)))
        b.extend(range(100, 110))
        self.assertEqual(list(b), list(range(10, 110)))

    def test_fifo_overrun(self):
        # Test for issue #23985, a buffer overrun when implementing a FIFO
        # Build Python in pydebug mode for best results.
        b = bytearray(10)
        b.pop()        # Defeat expanding buffer off-by-one quirk
        del b[:1]      # Advance start pointer without reallocating
        b += bytes(2)  # Append exactly the number of deleted bytes
        del b          # Free memory buffer, allowing pydebug verification

    def test_del_expand(self):
        # Reducing the size should not expand the buffer (issue #23985)
        b = bytearray(10)
        size = sys.getsizeof(b)
        del b[:1]
        self.assertLessEqual(sys.getsizeof(b), size)

    def test_extended_set_del_slice(self):
        indices = (0, None, 1, 3, 19, 300, 1<<333, sys.maxsize,
            -1, -2, -31, -300)
        for start in indices:
            for stop in indices:
                # Skip invalid step 0
                for step in indices[1:]:
                    L = list(range(255))
                    b = bytearray(L)
                    # Make sure we have a slice of exactly the right length,
                    # but with different data.
                    data = L[start:stop:step]
                    data.reverse()
                    L[start:stop:step] = data
                    b[start:stop:step] = data
                    self.assertEqual(b, bytearray(L))

                    del L[start:stop:step]
                    del b[start:stop:step]
                    self.assertEqual(b, bytearray(L))

    def test_setslice_trap(self):
        # This test verifies that we correctly handle assigning self
        # to a slice of self (the old Lambert Meertens trap).
        b = bytearray(range(256))
        b[8:] = b
        self.assertEqual(b, bytearray(list(range(8)) + list(range(256))))

    def test_iconcat(self):
        b = bytearray(b"abc")
        b1 = b
        b += b"def"
        self.assertEqual(b, b"abcdef")
        self.assertEqual(b, b1)
        self.assertIs(b, b1)
        b += b"xyz"
        self.assertEqual(b, b"abcdefxyz")
        try:
            b += ""
        except TypeError:
            pass
        else:
            self.fail("bytes += unicode didn't raise TypeError")

    def test_irepeat(self):
        b = bytearray(b"abc")
        b1 = b
        b *= 3
        self.assertEqual(b, b"abcabcabc")
        self.assertEqual(b, b1)
        self.assertIs(b, b1)

    def test_irepeat_1char(self):
        b = bytearray(b"x")
        b1 = b
        b *= 100
        self.assertEqual(b, b"x"*100)
        self.assertEqual(b, b1)
        self.assertIs(b, b1)

    def test_alloc(self):
        b = bytearray()
        alloc = b.__alloc__()
        self.assertGreaterEqual(alloc, 0)
        seq = [alloc]
        for i in range(100):
            b += b"x"
            alloc = b.__alloc__()
            self.assertGreater(alloc, len(b))  # including trailing null byte
            if alloc not in seq:
                seq.append(alloc)

    def test_init_alloc(self):
        b = bytearray()
        def g():
            for i in range(1, 100):
                yield i
                a = list(b)
                self.assertEqual(a, list(range(1, len(a)+1)))
                self.assertEqual(len(b), len(a))
                self.assertLessEqual(len(b), i)
                alloc = b.__alloc__()
                self.assertGreater(alloc, len(b))  # including trailing null byte
        b.__init__(g())
        self.assertEqual(list(b), list(range(1, 100)))
        self.assertEqual(len(b), 99)
        alloc = b.__alloc__()
        self.assertGreater(alloc, len(b))

    def test_extend(self):
        orig = b'hello'
        a = bytearray(orig)
        a.extend(a)
        self.assertEqual(a, orig + orig)
        self.assertEqual(a[5:], orig)
        a = bytearray(b'')
        # Test iterators that don't have a __length_hint__
        a.extend(map(int, orig * 25))
        a.extend(int(x) for x in orig * 25)
        self.assertEqual(a, orig * 50)
        self.assertEqual(a[-5:], orig)
        a = bytearray(b'')
        a.extend(iter(map(int, orig * 50)))
        self.assertEqual(a, orig * 50)
        self.assertEqual(a[-5:], orig)
        a = bytearray(b'')
        a.extend(list(map(int, orig * 50)))
        self.assertEqual(a, orig * 50)
        self.assertEqual(a[-5:], orig)
        a = bytearray(b'')
        self.assertRaises(ValueError, a.extend, [0, 1, 2, 256])
        self.assertRaises(ValueError, a.extend, [0, 1, 2, -1])
        self.assertEqual(len(a), 0)
        a = bytearray(b'')
        a.extend([Indexable(ord('a'))])
        self.assertEqual(a, b'a')
        a = bytearray(b'abc')
        self.assertRaisesRegex(TypeError,  # Override for string.
                               "expected iterable of integers; got: 'str'",
                               a.extend, 'def')
        self.assertRaisesRegex(TypeError,  # But not for others.
                               "can't extend bytearray with float",
                               a.extend, 1.0)

    def test_remove(self):
        b = bytearray(b'hello')
        b.remove(ord('l'))
        self.assertEqual(b, b'helo')
        b.remove(ord('l'))
        self.assertEqual(b, b'heo')
        self.assertRaises(ValueError, lambda: b.remove(ord('l')))
        self.assertRaises(ValueError, lambda: b.remove(400))
        self.assertRaises(TypeError, lambda: b.remove('e'))
        # remove first and last
        b.remove(ord('o'))
        b.remove(ord('h'))
        self.assertEqual(b, b'e')
        self.assertRaises(TypeError, lambda: b.remove(b'e'))
        b.remove(Indexable(ord('e')))
        self.assertEqual(b, b'')

        # test values outside of the ascii range: (0, 127)
        c = bytearray([126, 127, 128, 129])
        c.remove(127)
        self.assertEqual(c, bytes([126, 128, 129]))
        c.remove(129)
        self.assertEqual(c, bytes([126, 128]))

    def test_pop(self):
        b = bytearray(b'world')
        self.assertEqual(b.pop(), ord('d'))
        self.assertEqual(b.pop(0), ord('w'))
        self.assertEqual(b.pop(-2), ord('r'))
        self.assertRaises(IndexError, lambda: b.pop(10))
        self.assertRaises(IndexError, lambda: bytearray().pop())
        # test for issue #6846
        self.assertEqual(bytearray(b'\xff').pop(), 0xff)

    def test_nosort(self):
        self.assertRaises(AttributeError, lambda: bytearray().sort())

    def test_append(self):
        b = bytearray(b'hell')
        b.append(ord('o'))
        self.assertEqual(b, b'hello')
        self.assertEqual(b.append(100), None)
        b = bytearray()
        b.append(ord('A'))
        self.assertEqual(len(b), 1)
        self.assertRaises(TypeError, lambda: b.append(b'o'))
        b = bytearray()
        b.append(Indexable(ord('A')))
        self.assertEqual(b, b'A')

    def test_insert(self):
        b = bytearray(b'msssspp')
        b.insert(1, ord('i'))
        b.insert(4, ord('i'))
        b.insert(-2, ord('i'))
        b.insert(1000, ord('i'))
        self.assertEqual(b, b'mississippi')
        self.assertRaises(TypeError, lambda: b.insert(0, b'1'))
        b = bytearray()
        b.insert(0, Indexable(ord('A')))
        self.assertEqual(b, b'A')

    def test_copied(self):
        # Issue 4348.  Make sure that operations that don't mutate the array
        # copy the bytes.
        b = bytearray(b'abc')
        self.assertIsNot(b, b.replace(b'abc', b'cde', 0))

        t = bytearray([i for i in range(256)])
        x = bytearray(b'')
        self.assertIsNot(x, x.translate(t))

    def test_partition_bytearray_doesnt_share_nullstring(self):
        a, b, c = bytearray(b"x").partition(b"y")
        self.assertEqual(b, b"")
        self.assertEqual(c, b"")
        self.assertIsNot(b, c)
        b += b"!"
        self.assertEqual(c, b"")
        a, b, c = bytearray(b"x").partition(b"y")
        self.assertEqual(b, b"")
        self.assertEqual(c, b"")
        # Same for rpartition
        b, c, a = bytearray(b"x").rpartition(b"y")
        self.assertEqual(b, b"")
        self.assertEqual(c, b"")
        self.assertIsNot(b, c)
        b += b"!"
        self.assertEqual(c, b"")
        c, b, a = bytearray(b"x").rpartition(b"y")
        self.assertEqual(b, b"")
        self.assertEqual(c, b"")

    def test_resize_forbidden(self):
        # #4509: can't resize a bytearray when there are buffer exports, even
        # if it wouldn't reallocate the underlying buffer.
        # Furthermore, no destructive changes to the buffer may be applied
        # before raising the error.
        b = bytearray(10)
        v = memoryview(b)
        def manual_resize(n):
            b[1:-1] = range(n + 1, 2*n - 1)
        b.resize(10)
        orig = b[:]
        self.assertRaises(BufferError, b.resize, 11)
        self.assertRaises(BufferError, manual_resize, 11)
        self.assertEqual(b, orig)
        self.assertRaises(BufferError, b.resize, 9)
        self.assertEqual(b, orig)
        self.assertRaises(BufferError, b.resize, 0)
        self.assertEqual(b, orig)
        # Other operations implying resize
        self.assertRaises(BufferError, b.pop, 0)
        self.assertEqual(b, orig)
        self.assertRaises(BufferError, b.remove, b[1])
        self.assertEqual(b, orig)
        def delitem():
            del b[1]
        self.assertRaises(BufferError, delitem)
        self.assertEqual(b, orig)
        # deleting a non-contiguous slice
        def delslice():
            b[1:-1:2] = b""
        self.assertRaises(BufferError, delslice)
        self.assertEqual(b, orig)

    @test.support.cpython_only
    def test_obsolete_write_lock(self):
        _testcapi = import_helper.import_module('_testcapi')
        self.assertRaises(BufferError, _testcapi.getbuffer_with_null_view, bytearray())

    def test_iterator_pickling2(self):
        orig = bytearray(b'abc')
        data = list(b'qwerty')
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            # initial iterator
            itorig = iter(orig)
            d = pickle.dumps((itorig, orig), proto)
            it, b = pickle.loads(d)
            b[:] = data
            self.assertEqual(type(it), type(itorig))
            self.assertEqual(list(it), data)

            # running iterator
            next(itorig)
            d = pickle.dumps((itorig, orig), proto)
            it, b = pickle.loads(d)
            b[:] = data
            self.assertEqual(type(it), type(itorig))
            self.assertEqual(list(it), data[1:])

            # empty iterator
            for i in range(1, len(orig)):
                next(itorig)
            d = pickle.dumps((itorig, orig), proto)
            it, b = pickle.loads(d)
            b[:] = data
            self.assertEqual(type(it), type(itorig))
            self.assertEqual(list(it), data[len(orig):])

            # exhausted iterator
            self.assertRaises(StopIteration, next, itorig)
            d = pickle.dumps((itorig, orig), proto)
            it, b = pickle.loads(d)
            b[:] = data
            self.assertEqual(list(it), [])

    test_exhausted_iterator = test.list_tests.CommonTest.test_exhausted_iterator

    def test_iterator_length_hint(self):
        # Issue 27443: __length_hint__ can return negative integer
        ba = bytearray(b'ab')
        it = iter(ba)
        next(it)
        ba.clear()
        # Shouldn't raise an error
        self.assertEqual(list(it), [])

    def test_repeat_after_setslice(self):
        # bpo-42924: * used to copy from the wrong memory location
        b = bytearray(b'abc')
        b[:2] = b'x'
        b1 = b * 1
        b3 = b * 3
        self.assertEqual(b1, b'xc')
        self.assertEqual(b1, b)
        self.assertEqual(b3, b'xcxcxc')

    def test_mutating_index(self):
        # bytearray slice assignment can call into python code
        # that reallocates the internal buffer
        # See gh-91153

        class Boom:
            def __index__(self):
                b.clear()
                return 0

        with self.subTest("tp_as_mapping"):
            b = bytearray(b'Now you see me...')
            with self.assertRaises(IndexError):
                b[0] = Boom()

        with self.subTest("tp_as_sequence"):
            b = bytearray(b'Now you see me...')
            with self.assertRaises(IndexError):
                self._testlimitedcapi.sequence_setitem(b, 0, Boom())

    def test_mutating_index_inbounds(self):
        # gh-91153 continued
        # Ensure buffer is not broken even if length is correct

        class MutatesOnIndex:
            def __init__(self):
                self.ba = bytearray(0x180)

            def __index__(self):
                self.ba.clear()
                self.new_ba = bytearray(0x180)  # to catch out-of-bounds writes
                self.ba.extend([0] * 0x180)     # to check bounds checks
                return 0

        with self.subTest("skip_bounds_safety"):
            instance = MutatesOnIndex()
            instance.ba[instance] = ord("?")
            self.assertEqual(instance.ba[0], ord("?"), "Assigned bytearray not altered")
            self.assertEqual(instance.new_ba, bytearray(0x180), "Wrong object altered")

        with self.subTest("skip_bounds_safety_capi"):
            instance = MutatesOnIndex()
            instance.ba[instance] = ord("?")
            self._testlimitedcapi.sequence_setitem(instance.ba, instance, ord("?"))
            self.assertEqual(instance.ba[0], ord("?"), "Assigned bytearray not altered")
            self.assertEqual(instance.new_ba, bytearray(0x180), "Wrong object altered")

        with self.subTest("skip_bounds_safety_slice"):
            instance = MutatesOnIndex()
            instance.ba[instance:1] = [ord("?")]
            self.assertEqual(instance.ba[0], ord("?"), "Assigned bytearray not altered")
            self.assertEqual(instance.new_ba, bytearray(0x180), "Wrong object altered")

    def test_search_methods_reentrancy_raises_buffererror(self):
        # gh-142560: Raise BufferError if buffer mutates during search arg conversion.
        class Evil:
            def __init__(self, ba):
                self.ba = ba
            def __buffer__(self, flags):
                self.ba.clear()
                return memoryview(self.ba)
            def __release_buffer__(self, view: memoryview) -> None:
                view.release()
            def __index__(self):
                self.ba.clear()
                return ord("A")

        def make_case():
            ba = bytearray(b"A")
            return ba, Evil(ba)

        for name in ("find", "count", "index", "rindex", "rfind"):
            ba, evil = make_case()
            with self.subTest(name):
                with self.assertRaises(BufferError):
                    getattr(ba, name)(evil)

        ba, evil = make_case()
        with self.assertRaises(BufferError):
            evil in ba
        with self.assertRaises(BufferError):
            ba.split(evil)
        with self.assertRaises(BufferError):
            ba.rsplit(evil)

    def test_extend_empty_buffer_overflow(self):
        # gh-143003
        class EvilIter:
            def __iter__(self):
                return self
            def __next__(self):
                return next(source)
            def __length_hint__(self):
                return 0

        # Use ASCII digits so float() takes the fast path that expects a NUL terminator.
        source = iter(b'42')
        ba = bytearray()
        ba.extend(EvilIter())

        self.assertRaises(ValueError, float, bytearray())

    def test_hex_use_after_free(self):
        # Prevent UAF in bytearray.hex(sep) with re-entrant sep.__len__.
        # Regression test for https://github.com/python/cpython/issues/143195.
        ba = bytearray(b'\xAA')

        class S(bytes):
            def __len__(self):
                ba.clear()
                return 1

        self.assertRaises(BufferError, ba.hex, S(b':'))


class AssortedBytesTest(unittest.TestCase):
    #
    # Test various combinations of bytes and bytearray
    #

    def test_bytes_repr(self, f=repr):
        self.assertEqual(f(b''), "b''")
        self.assertEqual(f(b"abc"), "b'abc'")
        self.assertEqual(f(bytes([92])), r"b'\\'")
        self.assertEqual(f(bytes([0, 1, 254, 255])), r"b'\x00\x01\xfe\xff'")
        self.assertEqual(f(b'\a\b\t\n\v\f\r'), r"b'\x07\x08\t\n\x0b\x0c\r'")
        self.assertEqual(f(b'"'), """b'"'""") # '"'
        self.assertEqual(f(b"'"), '''b"'"''') # "'"
        self.assertEqual(f(b"'\""), r"""b'\'"'""") # '\'"'
        self.assertEqual(f(b"\"'\""), r"""b'"\'"'""") # '"\'"'
        self.assertEqual(f(b"'\"'"), r"""b'\'"\''""") # '\'"\''
        self.assertEqual(f(BytesSubclass(b"abc")), "b'abc'")

    def test_bytearray_repr(self, f=repr):
        self.assertEqual(f(bytearray()), "bytearray(b'')")
        self.assertEqual(f(bytearray(b'abc')), "bytearray(b'abc')")
        self.assertEqual(f(bytearray([92])), r"bytearray(b'\\')")
        self.assertEqual(f(bytearray([0, 1, 254, 255])),
                            r"bytearray(b'\x00\x01\xfe\xff')")
        self.assertEqual(f(bytearray([7, 8, 9, 10, 11, 12, 13])),
                            r"bytearray(b'\x07\x08\t\n\x0b\x0c\r')")
        self.assertEqual(f(bytearray(b'"')), """bytearray(b'"')""") # '"'
        self.assertEqual(f(bytearray(b"'")), '''bytearray(b"'")''') # "'"
        self.assertEqual(f(bytearray(b"'\"")), r"""bytearray(b'\'"')""") # '\'"'
        self.assertEqual(f(bytearray(b"\"'\"")), r"""bytearray(b'"\'"')""") # '"\'"'
        self.assertEqual(f(bytearray(b'\'"\'')), r"""bytearray(b'\'"\'')""") # '\'"\''
        self.assertEqual(f(ByteArraySubclass(b"abc")), "ByteArraySubclass(b'abc')")
        self.assertEqual(f(ByteArraySubclass.Nested(b"abc")), "Nested(b'abc')")
        self.assertEqual(f(ByteArraySubclass.Ŭñıçöđë(b"abc")), "Ŭñıçöđë(b'abc')")

    @check_bytes_warnings
    def test_bytes_str(self):
        self.test_bytes_repr(str)

    @check_bytes_warnings
    def test_bytearray_str(self):
        self.test_bytearray_repr(str)

    @check_bytes_warnings
    def test_format(self):
        for b in b'abc', bytearray(b'abc'):
            self.assertEqual(format(b), str(b))
            self.assertEqual(format(b, ''), str(b))
            with self.assertRaisesRegex(TypeError,
                                        r'\b%s\b' % re.escape(type(b).__name__)):
                format(b, 's')

    def test_compare_bytes_to_bytearray(self):
        self.assertEqual(b"abc" == bytes(b"abc"), True)
        self.assertEqual(b"ab" != bytes(b"abc"), True)
        self.assertEqual(b"ab" <= bytes(b"abc"), True)
        self.assertEqual(b"ab" < bytes(b"abc"), True)
        self.assertEqual(b"abc" >= bytes(b"ab"), True)
        self.assertEqual(b"abc" > bytes(b"ab"), True)

        self.assertEqual(b"abc" != bytes(b"abc"), False)
        self.assertEqual(b"ab" == bytes(b"abc"), False)
        self.assertEqual(b"ab" > bytes(b"abc"), False)
        self.assertEqual(b"ab" >= bytes(b"abc"), False)
        self.assertEqual(b"abc" < bytes(b"ab"), False)
        self.assertEqual(b"abc" <= bytes(b"ab"), False)

        self.assertEqual(bytes(b"abc") == b"abc", True)
        self.assertEqual(bytes(b"ab") != b"abc", True)
        self.assertEqual(bytes(b"ab") <= b"abc", True)
        self.assertEqual(bytes(b"ab") < b"abc", True)
        self.assertEqual(bytes(b"abc") >= b"ab", True)
        self.assertEqual(bytes(b"abc") > b"ab", True)

        self.assertEqual(bytes(b"abc") != b"abc", False)
        self.assertEqual(bytes(b"ab") == b"abc", False)
        self.assertEqual(bytes(b"ab") > b"abc", False)
        self.assertEqual(bytes(b"ab") >= b"abc", False)
        self.assertEqual(bytes(b"abc") < b"ab", False)
        self.assertEqual(bytes(b"abc") <= b"ab", False)

    @test.support.requires_docstrings
    def test_doc(self):
        self.assertIsNotNone(bytearray.__doc__)
        self.assertStartsWith(bytearray.__doc__, "bytearray(")
        self.assertIsNotNone(bytes.__doc__)
        self.assertStartsWith(bytes.__doc__, "bytes(")

    def test_from_bytearray(self):
        sample = bytes(b"Hello world\n\x80\x81\xfe\xff")
        buf = memoryview(sample)
        b = bytearray(buf)
        self.assertEqual(b, bytearray(sample))

    def test_literal(self):
        tests =  [
            (b"Wonderful spam", "Wonderful spam"),
            (br"Wonderful spam too", "Wonderful spam too"),
            (b"\xaa\x00\000\200", "\xaa\x00\000\200"),
            (br"\xaa\x00\000\200", r"\xaa\x00\000\200"),
        ]
        for b, s in tests:
            self.assertEqual(b, bytearray(s, 'latin-1'))
        for c in range(128, 256):
            self.assertRaises(SyntaxError, eval,
                              'b"%s"' % chr(c))

    def test_split_bytearray(self):
        self.assertEqual(b'a b'.split(memoryview(b' ')), [b'a', b'b'])

    def test_rsplit_bytearray(self):
        self.assertEqual(b'a b'.rsplit(memoryview(b' ')), [b'a', b'b'])

    def test_return_self(self):
        # bytearray.replace must always return a new bytearray
        b = bytearray()
        self.assertIsNot(b.replace(b'', b''), b)

    @unittest.skipUnless(sys.flags.bytes_warning,
                         "BytesWarning is needed for this test: use -bb option")
    def test_compare(self):
        def bytes_warning():
            return warnings_helper.check_warnings(('', BytesWarning))
        with bytes_warning():
            b'' == ''
        with bytes_warning():
            '' == b''
        with bytes_warning():
            b'' != ''
        with bytes_warning():
            '' != b''
        with bytes_warning():
            bytearray(b'') == ''
        with bytes_warning():
            '' == bytearray(b'')
        with bytes_warning():
            bytearray(b'') != ''
        with bytes_warning():
            '' != bytearray(b'')
        with bytes_warning():
            b'\0' == 0
        with bytes_warning():
            0 == b'\0'
        with bytes_warning():
            b'\0' != 0
        with bytes_warning():
            0 != b'\0'

    # Optimizations:
    # __iter__? (optimization)
    # __reversed__? (optimization)

    # XXX More string methods?  (Those that don't use character properties)

    # There are tests in string_tests.py that are more
    # comprehensive for things like partition, etc.
    # Unfortunately they are all bundled with tests that
    # are not appropriate for bytes

    # I've started porting some of those into bytearray_tests.py, we should port
    # the rest that make sense (the code can be cleaned up to use modern
    # unittest methods at the same time).

class BytearrayPEP3137Test(unittest.TestCase):
    def marshal(self, x):
        return bytearray(x)

    def test_returns_new_copy(self):
        val = self.marshal(b'1234')
        # On immutable types these MAY return a reference to themselves
        # but on mutable types like bytearray they MUST return a new copy.
        for methname in ('zfill', 'rjust', 'ljust', 'center'):
            method = getattr(val, methname)
            newval = method(3)
            self.assertEqual(val, newval)
            self.assertIsNot(val, newval,
                            methname+' returned self on a mutable object')
        for expr in ('val.split()[0]', 'val.rsplit()[0]',
                     'val.partition(b".")[0]', 'val.rpartition(b".")[2]',
                     'val.splitlines()[0]', 'val.replace(b"", b"")'):
            newval = eval(expr)
            self.assertEqual(val, newval)
            self.assertIsNot(val, newval,
                            expr+' returned val on a mutable object')
        sep = self.marshal(b'')
        newval = sep.join([val])
        self.assertEqual(val, newval)
        self.assertIsNot(val, newval)


class FixedStringTest(test.string_tests.BaseTest):
    def fixtype(self, obj):
        if isinstance(obj, str):
            return self.type2test(obj.encode("utf-8"))
        return super().fixtype(obj)

    contains_bytes = True

    def test_mixed_cmp(self):
        a = self.type2test(b'ab')
        for t in bytes, bytearray, BytesSubclass, ByteArraySubclass:
            with self.subTest(t.__name__):
                self._assert_cmp(a, t(b'ab'), 0)
                self._assert_cmp(a, t(b'a'), 1)
                self._assert_cmp(a, t(b'ac'), -1)

class ByteArrayAsStringTest(FixedStringTest, unittest.TestCase):
    type2test = bytearray

class BytesAsStringTest(FixedStringTest, unittest.TestCase):
    type2test = bytes

class SubclassTest:

    def test_basic(self):
        self.assertIsSubclass(self.type2test, self.basetype)
        self.assertIsInstance(self.type2test(), self.basetype)

        a, b = b"abcd", b"efgh"
        _a, _b = self.type2test(a), self.type2test(b)

        # test comparison operators with subclass instances
        self.assertTrue(_a == _a)
        self.assertTrue(_a != _b)
        self.assertTrue(_a < _b)
        self.assertTrue(_a <= _b)
        self.assertTrue(_b >= _a)
        self.assertTrue(_b > _a)
        self.assertIsNot(_a, a)

        # test concat of subclass instances
        self.assertEqual(a + b, _a + _b)
        self.assertEqual(a + b, a + _b)
        self.assertEqual(a + b, _a + b)

        # test repeat
        self.assertTrue(a*5 == _a*5)

    def test_join(self):
        # Make sure join returns a NEW object for single item sequences
        # involving a subclass.
        # Make sure that it is of the appropriate type.
        s1 = self.type2test(b"abcd")
        s2 = self.basetype().join([s1])
        self.assertIsNot(s1, s2)
        self.assertIs(type(s2), self.basetype, type(s2))

        # Test reverse, calling join on subclass
        s3 = s1.join([b"abcd"])
        self.assertIs(type(s3), self.basetype)

    def test_pickle(self):
        a = self.type2test(b"abcd")
        a.x = 10
        a.z = self.type2test(b"efgh")
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            b = pickle.loads(pickle.dumps(a, proto))
            self.assertNotEqual(id(a), id(b))
            self.assertEqual(a, b)
            self.assertEqual(a.x, b.x)
            self.assertEqual(a.z, b.z)
            self.assertEqual(type(a), type(b))
            self.assertEqual(type(a.z), type(b.z))
            self.assertNotHasAttr(b, 'y')

    def test_copy(self):
        a = self.type2test(b"abcd")
        a.x = 10
        a.z = self.type2test(b"efgh")
        for copy_method in (copy.copy, copy.deepcopy):
            b = copy_method(a)
            self.assertNotEqual(id(a), id(b))
            self.assertEqual(a, b)
            self.assertEqual(a.x, b.x)
            self.assertEqual(a.z, b.z)
            self.assertEqual(type(a), type(b))
            self.assertEqual(type(a.z), type(b.z))
            self.assertNotHasAttr(b, 'y')

    def test_fromhex(self):
        b = self.type2test.fromhex('1a2B30')
        self.assertEqual(b, b'\x1a\x2b\x30')
        self.assertIs(type(b), self.type2test)

        class B1(self.basetype):
            def __new__(cls, value):
                me = self.basetype.__new__(cls, value)
                me.foo = 'bar'
                return me

        b = B1.fromhex('1a2B30')
        self.assertEqual(b, b'\x1a\x2b\x30')
        self.assertIs(type(b), B1)
        self.assertEqual(b.foo, 'bar')

        class B2(self.basetype):
            def __init__(me, *args, **kwargs):
                if self.basetype is not bytes:
                    self.basetype.__init__(me, *args, **kwargs)
                me.foo = 'bar'

        b = B2.fromhex('1a2B30')
        self.assertEqual(b, b'\x1a\x2b\x30')
        self.assertIs(type(b), B2)
        self.assertEqual(b.foo, 'bar')


class ByteArraySubclass(bytearray):
    class Nested(bytearray):
        pass
    class Ŭñıçöđë(bytearray):
        pass

class ByteArraySubclassWithSlots(bytearray):
    __slots__ = ('x', 'y', '__dict__')

class BytesSubclass(bytes):
    pass

class OtherBytesSubclass(bytes):
    pass

class WithBytes:
    def __init__(self, value):
        self.value = value
    def __bytes__(self):
        return self.value

class ByteArraySubclassTest(SubclassTest, unittest.TestCase):
    basetype = bytearray
    type2test = ByteArraySubclass

    def test_init_override(self):
        class subclass(bytearray):
            def __init__(me, newarg=1, *args, **kwargs):
                bytearray.__init__(me, *args, **kwargs)
        x = subclass(4, b"abcd")
        x = subclass(4, source=b"abcd")
        self.assertEqual(x, b"abcd")
        x = subclass(newarg=4, source=b"abcd")
        self.assertEqual(x, b"abcd")

class ByteArraySubclassWithSlotsTest(SubclassTest, unittest.TestCase):
    basetype = bytearray
    type2test = ByteArraySubclassWithSlots

class BytesSubclassTest(SubclassTest, unittest.TestCase):
    basetype = bytes
    type2test = BytesSubclass


class FreeThreadingTest(unittest.TestCase):
    @unittest.skipUnless(support.Py_GIL_DISABLED, 'this test can only possibly fail with GIL disabled')
    @threading_helper.reap_threads
    @threading_helper.requires_working_threading()
    def test_free_threading_bytearray(self):
        # Test pretty much everything that can break under free-threading.
        # Non-deterministic, but at least one of these things will fail if
        # bytearray module is not free-thread safe.

        def clear(b, a, *args):  # MODIFIES!
            b.wait()
            try: a.clear()
            except BufferError: pass

        def clear2(b, a, c):  # MODIFIES c!
            b.wait()
            try: c.clear()
            except BufferError: pass

        def pop1(b, a):  # MODIFIES!
            b.wait()
            try: a.pop()
            except IndexError: pass

        def append1(b, a):  # MODIFIES!
            b.wait()
            a.append(0)

        def insert1(b, a):  # MODIFIES!
            b.wait()
            a.insert(0, 0)

        def extend(b, a):  # MODIFIES!
            c = bytearray(b'0' * 0x400000)
            b.wait()
            a.extend(c)

        def remove(b, a):  # MODIFIES!
            c = ord('0')
            b.wait()
            try: a.remove(c)
            except ValueError: pass

        def reverse(b, a):  # modifies inplace
            b.wait()
            a.reverse()

        def reduce(b, a):
            b.wait()
            a.__reduce__()

        def reduceex2(b, a):
            b.wait()
            a.__reduce_ex__(2)

        def reduceex3(b, a):
            b.wait()
            c = a.__reduce_ex__(3)
            assert not c[1] or 0xdd not in c[1][0]

        def count0(b, a):
            b.wait()
            a.count(0)

        def decode(b, a):
            b.wait()
            a.decode()

        def find(b, a):
            c = bytearray(b'0' * 0x40000)
            b.wait()
            a.find(c)

        def hex(b, a):
            b.wait()
            a.hex('_')

        def join(b, a):
            b.wait()
            a.join([b'1', b'2', b'3'])

        def replace(b, a):
            b.wait()
            a.replace(b'0', b'')

        def maketrans(b, a, c):
            b.wait()
            try: a.maketrans(a, c)
            except ValueError: pass

        def translate(b, a, c):
            b.wait()
            a.translate(c)

        def copy(b, a):
            b.wait()
            c = a.copy()
            if c: assert c[0] == 48  # '0'

        def endswith(b, a):
            b.wait()
            assert not a.endswith(b'\xdd')

        def index(b, a):
            b.wait()
            try: a.index(b'\xdd')
            except ValueError: return
            assert False

        def lstrip(b, a):
            b.wait()
            assert not a.lstrip(b'0')

        def partition(b, a):
            b.wait()
            assert not a.partition(b'\xdd')[2]

        def removeprefix(b, a):
            b.wait()
            assert not a.removeprefix(b'0')

        def removesuffix(b, a):
            b.wait()
            assert not a.removesuffix(b'0')

        def rfind(b, a):
            b.wait()
            assert a.rfind(b'\xdd') == -1

        def rindex(b, a):
            b.wait()
            try: a.rindex(b'\xdd')
            except ValueError: return
            assert False

        def rpartition(b, a):
            b.wait()
            assert not a.rpartition(b'\xdd')[0]

        def rsplit(b, a):
            b.wait()
            assert len(a.rsplit(b'\xdd')) == 1

        def rstrip(b, a):
            b.wait()
            assert not a.rstrip(b'0')

        def split(b, a):
            b.wait()
            assert len(a.split(b'\xdd')) == 1

        def splitlines(b, a):
            b.wait()
            l = len(a.splitlines())
            assert l > 1 or l == 0

        def startswith(b, a):
            b.wait()
            assert not a.startswith(b'\xdd')

        def strip(b, a):
            b.wait()
            assert not a.strip(b'0')

        def repeat(b, a):
            b.wait()
            a * 2

        def contains(b, a):
            b.wait()
            assert 0xdd not in a

        def iconcat(b, a):  # MODIFIES!
            c = bytearray(b'0' * 0x400000)
            b.wait()
            a += c

        def irepeat(b, a):  # MODIFIES!
            b.wait()
            a *= 2

        def subscript(b, a):
            b.wait()
            try: assert a[0] != 0xdd
            except IndexError: pass

        def ass_subscript(b, a):  # MODIFIES!
            c = bytearray(b'0' * 0x400000)
            b.wait()
            a[:] = c

        def ass_subscript2(b, a, c):  # MODIFIES!
            b.wait()
            a[:] = c
            assert b'\xdd' not in a

        def mod(b, a):
            c = tuple(range(4096))
            b.wait()
            try: a % c
            except TypeError: pass

        def mod2(b, a, c):
            b.wait()
            d = a % c
            assert b'\xdd' not in d

        def repr_(b, a):
            b.wait()
            repr(a)

        def capitalize(b, a):
            b.wait()
            c = a.capitalize()
            assert not c or c[0] not in (0xdd, 0xcd)

        def center(b, a):
            b.wait()
            c = a.center(0x60000)
            assert not c or c[0x20000] not in (0xdd, 0xcd)

        def expandtabs(b, a):
            b.wait()
            c = a.expandtabs()
            assert not c or c[0] not in (0xdd, 0xcd)

        def ljust(b, a):
            b.wait()
            c = a.ljust(0x600000)
            assert not c or c[0] not in (0xdd, 0xcd)

        def lower(b, a):
            b.wait()
            c = a.lower()
            assert not c or c[0] not in (0xdd, 0xcd)

        def rjust(b, a):
            b.wait()
            c = a.rjust(0x600000)
            assert not c or c[-1] not in (0xdd, 0xcd)

        def swapcase(b, a):
            b.wait()
            c = a.swapcase()
            assert not c or c[-1] not in (0xdd, 0xcd)

        def title(b, a):
            b.wait()
            c = a.title()
            assert not c or c[-1] not in (0xdd, 0xcd)

        def upper(b, a):
            b.wait()
            c = a.upper()
            assert not c or c[-1] not in (0xdd, 0xcd)

        def zfill(b, a):
            b.wait()
            c = a.zfill(0x400000)
            assert not c or c[-1] not in (0xdd, 0xcd)

        def resize(b, a):  # MODIFIES!
            b.wait()
            a.resize(10)

        def take_bytes(b, a):  # MODIFIES!
            b.wait()
            c = a.take_bytes()
            assert not c or c[0] == 48  # '0'

        def take_bytes_n(b, a):  # MODIFIES!
            b.wait()
            try:
                c = a.take_bytes(10)
                assert c == b'0123456789'
            except IndexError: pass

        def check(funcs, a=None, *args):
            if a is None:
                a = bytearray(b'0' * 0x400000)

            barrier = threading.Barrier(len(funcs))
            threads = []

            for func in funcs:
                thread = threading.Thread(target=func, args=(barrier, a, *args))

                threads.append(thread)

            with threading_helper.start_threads(threads):
                pass

        # hard errors

        check([clear] + [reduce] * 10)
        check([clear] + [reduceex2] * 10)
        check([clear] + [append1] * 10)
        check([clear] * 10)
        check([clear] + [count0] * 10)
        check([clear] + [decode] * 10)
        check([clear] + [extend] * 10)
        check([clear] + [find] * 10)
        check([clear] + [hex] * 10)
        check([clear] + [insert1] * 10)
        check([clear] + [join] * 10)
        check([clear] + [pop1] * 10)
        check([clear] + [remove] * 10)
        check([clear] + [replace] * 10)
        check([clear] + [reverse] * 10)
        check([clear, clear2] + [maketrans] * 10, bytearray(range(128)), bytearray(range(128)))
        check([clear] + [translate] * 10, None, bytearray.maketrans(bytearray(range(128)), bytearray(range(128))))

        check([clear] + [repeat] * 10)
        check([clear] + [iconcat] * 10)
        check([clear] + [irepeat] * 10)
        check([clear] + [ass_subscript] * 10)
        check([clear] + [repr_] * 10)

        # value errors

        check([clear] + [reduceex3] * 10, bytearray(b'a' * 0x40000))
        check([clear] + [copy] * 10)
        check([clear] + [endswith] * 10)
        check([clear] + [index] * 10)
        check([clear] + [lstrip] * 10)
        check([clear] + [partition] * 10)
        check([clear] + [removeprefix] * 10, bytearray(b'0'))
        check([clear] + [removesuffix] * 10, bytearray(b'0'))
        check([clear] + [rfind] * 10)
        check([clear] + [rindex] * 10)
        check([clear] + [rpartition] * 10)
        check([clear] + [rsplit] * 10, bytearray(b'0' * 0x4000))
        check([clear] + [rstrip] * 10)
        check([clear] + [split] * 10, bytearray(b'0' * 0x4000))
        check([clear] + [splitlines] * 10, bytearray(b'\n' * 0x400))
        check([clear] + [startswith] * 10)
        check([clear] + [strip] * 10)

        check([clear] + [resize] * 10)

        check([clear] + [take_bytes] * 10)
        check([take_bytes_n] * 10, bytearray(b'0123456789' * 0x400))
        check([take_bytes_n] * 10, bytearray(b'0123456789' * 5))

        check([clear] + [contains] * 10)
        check([clear] + [subscript] * 10)
        check([clear2] + [ass_subscript2] * 10, None, bytearray(b'0' * 0x400000))
        check([clear] + [mod] * 10, bytearray(b'%d' * 4096))
        check([clear2] + [mod2] * 10, bytearray(b'%s'), bytearray(b'0' * 0x400000))

        check([clear] + [capitalize] * 10, bytearray(b'a' * 0x40000))
        check([clear] + [center] * 10, bytearray(b'a' * 0x40000))
        check([clear] + [expandtabs] * 10, bytearray(b'0\t' * 4096))
        check([clear] + [ljust] * 10, bytearray(b'0' * 0x400000))
        check([clear] + [lower] * 10, bytearray(b'A' * 0x400000))
        check([clear] + [rjust] * 10, bytearray(b'0' * 0x400000))
        check([clear] + [swapcase] * 10, bytearray(b'aA' * 0x200000))
        check([clear] + [title] * 10, bytearray(b'aA' * 0x200000))
        check([clear] + [upper] * 10, bytearray(b'a' * 0x400000))
        check([clear] + [zfill] * 10, bytearray(b'1' * 0x200000))

    @unittest.skipUnless(support.Py_GIL_DISABLED, 'this test can only possibly fail with GIL disabled')
    @threading_helper.reap_threads
    @threading_helper.requires_working_threading()
    def test_free_threading_bytearrayiter(self):
        # Non-deterministic but good chance to fail if bytearrayiter is not free-threading safe.
        # We are fishing for a "Assertion failed: object has negative ref count" and tsan races.

        def iter_next(b, it):
            b.wait()
            list(it)

        def iter_reduce(b, it):
            b.wait()
            it.__reduce__()

        def iter_setstate(b, it):
            b.wait()
            it.__setstate__(0)

        def check(funcs, it):
            barrier = threading.Barrier(len(funcs))
            threads = []

            for func in funcs:
                thread = threading.Thread(target=func, args=(barrier, it))

                threads.append(thread)

            with threading_helper.start_threads(threads):
                pass

        for _ in range(10):
            ba = bytearray(b'0' * 0x4000)  # this is a load-bearing variable, do not remove

            check([iter_next] * 10, iter(ba))
            check([iter_next] + [iter_reduce] * 10, iter(ba))  # for tsan
            check([iter_next] + [iter_setstate] * 10, iter(ba))  # for tsan

    @unittest.skipUnless(support.Py_GIL_DISABLED, 'this test can only possibly fail with GIL disabled')
    @threading_helper.reap_threads
    @threading_helper.requires_working_threading()
    def test_free_threading_bytearray_resize(self):
        def resize_stress(ba):
            for _ in range(1000):
                try:
                    ba.resize(1000)
                    ba.resize(1)
                except (BufferError, ValueError):
                    pass

        ba = bytearray(100)
        threads = [threading.Thread(target=resize_stress, args=(ba,)) for _ in range(4)]
        with threading_helper.start_threads(threads):
            pass

if __name__ == "__main__":
    unittest.main()