test_re.py

from test.support import (gc_collect, bigmemtest, _2G,
                          cpython_only, captured_stdout)
import locale
import re
import sre_compile
import string
import unittest
import warnings
from re import Scanner
from weakref import proxy

# Misc tests from Tim Peters' re.doc

# WARNING: Don't change details in these tests if you don't know
# what you're doing. Some of these tests were carefully modeled to
# cover most of the code.

class S(str):
    def __getitem__(self, index):
        return S(super().__getitem__(index))

class B(bytes):
    def __getitem__(self, index):
        return B(super().__getitem__(index))

class ReTests(unittest.TestCase):

    def assertTypedEqual(self, actual, expect, msg=None):
        self.assertEqual(actual, expect, msg)
        def recurse(actual, expect):
            if isinstance(expect, (tuple, list)):
                for x, y in zip(actual, expect):
                    recurse(x, y)
            else:
                self.assertIs(type(actual), type(expect), msg)
        recurse(actual, expect)

    def checkPatternError(self, pattern, errmsg, pos=None):
        with self.assertRaises(re.error) as cm:
            re.compile(pattern)
        with self.subTest(pattern=pattern):
            err = cm.exception
            self.assertEqual(err.msg, errmsg)
            if pos is not None:
                self.assertEqual(err.pos, pos)

    def checkTemplateError(self, pattern, repl, string, errmsg, pos=None):
        with self.assertRaises(re.error) as cm:
            re.sub(pattern, repl, string)
        with self.subTest(pattern=pattern, repl=repl):
            err = cm.exception
            self.assertEqual(err.msg, errmsg)
            if pos is not None:
                self.assertEqual(err.pos, pos)

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_keep_buffer(self):
        # See bug 14212
        b = bytearray(b'x')
        it = re.finditer(b'a', b)
        with self.assertRaises(BufferError):
            b.extend(b'x'*400)
        list(it)
        del it
        gc_collect()
        b.extend(b'x'*400)

    def test_weakref(self):
        s = 'QabbbcR'
        x = re.compile('ab+c')
        y = proxy(x)
        self.assertEqual(x.findall('QabbbcR'), y.findall('QabbbcR'))

    def test_search_star_plus(self):
        self.assertEqual(re.search('x*', 'axx').span(0), (0, 0))
        self.assertEqual(re.search('x*', 'axx').span(), (0, 0))
        self.assertEqual(re.search('x+', 'axx').span(0), (1, 3))
        self.assertEqual(re.search('x+', 'axx').span(), (1, 3))
        self.assertIsNone(re.search('x', 'aaa'))
        self.assertEqual(re.match('a*', 'xxx').span(0), (0, 0))
        self.assertEqual(re.match('a*', 'xxx').span(), (0, 0))
        self.assertEqual(re.match('x*', 'xxxa').span(0), (0, 3))
        self.assertEqual(re.match('x*', 'xxxa').span(), (0, 3))
        self.assertIsNone(re.match('a+', 'xxx'))

    def bump_num(self, matchobj):
        int_value = int(matchobj.group(0))
        return str(int_value + 1)

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_basic_re_sub(self):
        self.assertTypedEqual(re.sub('y', 'a', 'xyz'), 'xaz')
        self.assertTypedEqual(re.sub('y', S('a'), S('xyz')), 'xaz')
        self.assertTypedEqual(re.sub(b'y', b'a', b'xyz'), b'xaz')
        self.assertTypedEqual(re.sub(b'y', B(b'a'), B(b'xyz')), b'xaz')
        self.assertTypedEqual(re.sub(b'y', bytearray(b'a'), bytearray(b'xyz')), b'xaz')
        self.assertTypedEqual(re.sub(b'y', memoryview(b'a'), memoryview(b'xyz')), b'xaz')
        for y in ("\xe0", "\u0430", "\U0001d49c"):
            self.assertEqual(re.sub(y, 'a', 'x%sz' % y), 'xaz')

        self.assertEqual(re.sub("(?i)b+", "x", "bbbb BBBB"), 'x x')
        self.assertEqual(re.sub(r'\d+', self.bump_num, '08.2 -2 23x99y'),
                         '9.3 -3 24x100y')
        self.assertEqual(re.sub(r'\d+', self.bump_num, '08.2 -2 23x99y', 3),
                         '9.3 -3 23x99y')
        self.assertEqual(re.sub(r'\d+', self.bump_num, '08.2 -2 23x99y', count=3),
                         '9.3 -3 23x99y')

        self.assertEqual(re.sub('.', lambda m: r"\n", 'x'), '\\n')
        self.assertEqual(re.sub('.', r"\n", 'x'), '\n')

        s = r"\1\1"
        self.assertEqual(re.sub('(.)', s, 'x'), 'xx')
        self.assertEqual(re.sub('(.)', s.replace('\\', r'\\'), 'x'), s)
        self.assertEqual(re.sub('(.)', lambda m: s, 'x'), s)

        self.assertEqual(re.sub('(?P<a>x)', r'\g<a>\g<a>', 'xx'), 'xxxx')
        self.assertEqual(re.sub('(?P<a>x)', r'\g<a>\g<1>', 'xx'), 'xxxx')
        self.assertEqual(re.sub('(?P<unk>x)', r'\g<unk>\g<unk>', 'xx'), 'xxxx')
        self.assertEqual(re.sub('(?P<unk>x)', r'\g<1>\g<1>', 'xx'), 'xxxx')

        self.assertEqual(re.sub('a', r'\t\n\v\r\f\a\b', 'a'), '\t\n\v\r\f\a\b')
        self.assertEqual(re.sub('a', '\t\n\v\r\f\a\b', 'a'), '\t\n\v\r\f\a\b')
        self.assertEqual(re.sub('a', '\t\n\v\r\f\a\b', 'a'),
                         (chr(9)+chr(10)+chr(11)+chr(13)+chr(12)+chr(7)+chr(8)))
        for c in 'cdehijklmopqsuwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ':
            with self.subTest(c):
                with self.assertRaises(re.error):
                    self.assertEqual(re.sub('a', '\\' + c, 'a'), '\\' + c)

        self.assertEqual(re.sub(r'^\s*', 'X', 'test'), 'Xtest')

    def test_bug_449964(self):
        # fails for group followed by other escape
        self.assertEqual(re.sub(r'(?P<unk>x)', r'\g<1>\g<1>\b', 'xx'),
                         'xx\bxx\b')

    def test_bug_449000(self):
        # Test for sub() on escaped characters
        self.assertEqual(re.sub(r'\r\n', r'\n', 'abc\r\ndef\r\n'),
                         'abc\ndef\n')
        self.assertEqual(re.sub('\r\n', r'\n', 'abc\r\ndef\r\n'),
                         'abc\ndef\n')
        self.assertEqual(re.sub(r'\r\n', '\n', 'abc\r\ndef\r\n'),
                         'abc\ndef\n')
        self.assertEqual(re.sub('\r\n', '\n', 'abc\r\ndef\r\n'),
                         'abc\ndef\n')

    def test_bug_1661(self):
        # Verify that flags do not get silently ignored with compiled patterns
        pattern = re.compile('.')
        self.assertRaises(ValueError, re.match, pattern, 'A', re.I)
        self.assertRaises(ValueError, re.search, pattern, 'A', re.I)
        self.assertRaises(ValueError, re.findall, pattern, 'A', re.I)
        self.assertRaises(ValueError, re.compile, pattern, re.I)

    def test_bug_3629(self):
        # A regex that triggered a bug in the sre-code validator
        re.compile("(?P<quote>)(?(quote))")

    def test_sub_template_numeric_escape(self):
        # bug 776311 and friends
        self.assertEqual(re.sub('x', r'\0', 'x'), '\0')
        self.assertEqual(re.sub('x', r'\000', 'x'), '\000')
        self.assertEqual(re.sub('x', r'\001', 'x'), '\001')
        self.assertEqual(re.sub('x', r'\008', 'x'), '\0' + '8')
        self.assertEqual(re.sub('x', r'\009', 'x'), '\0' + '9')
        self.assertEqual(re.sub('x', r'\111', 'x'), '\111')
        self.assertEqual(re.sub('x', r'\117', 'x'), '\117')
        self.assertEqual(re.sub('x', r'\377', 'x'), '\377')

        self.assertEqual(re.sub('x', r'\1111', 'x'), '\1111')
        self.assertEqual(re.sub('x', r'\1111', 'x'), '\111' + '1')

        self.assertEqual(re.sub('x', r'\00', 'x'), '\x00')
        self.assertEqual(re.sub('x', r'\07', 'x'), '\x07')
        self.assertEqual(re.sub('x', r'\08', 'x'), '\0' + '8')
        self.assertEqual(re.sub('x', r'\09', 'x'), '\0' + '9')
        self.assertEqual(re.sub('x', r'\0a', 'x'), '\0' + 'a')

        self.checkTemplateError('x', r'\400', 'x',
                                r'octal escape value \400 outside of '
                                r'range 0-0o377', 0)
        self.checkTemplateError('x', r'\777', 'x',
                                r'octal escape value \777 outside of '
                                r'range 0-0o377', 0)

        self.checkTemplateError('x', r'\1', 'x', 'invalid group reference 1', 1)
        self.checkTemplateError('x', r'\8', 'x', 'invalid group reference 8', 1)
        self.checkTemplateError('x', r'\9', 'x', 'invalid group reference 9', 1)
        self.checkTemplateError('x', r'\11', 'x', 'invalid group reference 11', 1)
        self.checkTemplateError('x', r'\18', 'x', 'invalid group reference 18', 1)
        self.checkTemplateError('x', r'\1a', 'x', 'invalid group reference 1', 1)
        self.checkTemplateError('x', r'\90', 'x', 'invalid group reference 90', 1)
        self.checkTemplateError('x', r'\99', 'x', 'invalid group reference 99', 1)
        self.checkTemplateError('x', r'\118', 'x', 'invalid group reference 11', 1)
        self.checkTemplateError('x', r'\11a', 'x', 'invalid group reference 11', 1)
        self.checkTemplateError('x', r'\181', 'x', 'invalid group reference 18', 1)
        self.checkTemplateError('x', r'\800', 'x', 'invalid group reference 80', 1)
        self.checkTemplateError('x', r'\8', '', 'invalid group reference 8', 1)

        # in python2.3 (etc), these loop endlessly in sre_parser.py
        self.assertEqual(re.sub('(((((((((((x)))))))))))', r'\11', 'x'), 'x')
        self.assertEqual(re.sub('((((((((((y))))))))))(.)', r'\118', 'xyz'),
                         'xz8')
        self.assertEqual(re.sub('((((((((((y))))))))))(.)', r'\11a', 'xyz'),
                         'xza')

    def test_qualified_re_sub(self):
        self.assertEqual(re.sub('a', 'b', 'aaaaa'), 'bbbbb')
        self.assertEqual(re.sub('a', 'b', 'aaaaa', 1), 'baaaa')
        self.assertEqual(re.sub('a', 'b', 'aaaaa', count=1), 'baaaa')

    def test_bug_114660(self):
        self.assertEqual(re.sub(r'(\S)\s+(\S)', r'\1 \2', 'hello  there'),
                         'hello there')

    def test_symbolic_groups(self):
        re.compile(r'(?P<a>x)(?P=a)(?(a)y)')
        re.compile(r'(?P<a1>x)(?P=a1)(?(a1)y)')
        re.compile(r'(?P<a1>x)\1(?(1)y)')
        self.checkPatternError(r'(?P<a>)(?P<a>)',
                               "redefinition of group name 'a' as group 2; "
                               "was group 1")
        self.checkPatternError(r'(?P<a>(?P=a))',
                               "cannot refer to an open group", 10)
        self.checkPatternError(r'(?Pxy)', 'unknown extension ?Px')
        self.checkPatternError(r'(?P<a>)(?P=a', 'missing ), unterminated name', 11)
        self.checkPatternError(r'(?P=', 'missing group name', 4)
        self.checkPatternError(r'(?P=)', 'missing group name', 4)
        self.checkPatternError(r'(?P=1)', "bad character in group name '1'", 4)
        self.checkPatternError(r'(?P=a)', "unknown group name 'a'")
        self.checkPatternError(r'(?P=a1)', "unknown group name 'a1'")
        self.checkPatternError(r'(?P=a.)', "bad character in group name 'a.'", 4)
        self.checkPatternError(r'(?P<)', 'missing >, unterminated name', 4)
        self.checkPatternError(r'(?P<a', 'missing >, unterminated name', 4)
        self.checkPatternError(r'(?P<', 'missing group name', 4)
        self.checkPatternError(r'(?P<>)', 'missing group name', 4)
        self.checkPatternError(r'(?P<1>)', "bad character in group name '1'", 4)
        self.checkPatternError(r'(?P<a.>)', "bad character in group name 'a.'", 4)
        self.checkPatternError(r'(?(', 'missing group name', 3)
        self.checkPatternError(r'(?())', 'missing group name', 3)
        self.checkPatternError(r'(?(a))', "unknown group name 'a'", 3)
        self.checkPatternError(r'(?(-1))', "bad character in group name '-1'", 3)
        self.checkPatternError(r'(?(1a))', "bad character in group name '1a'", 3)
        self.checkPatternError(r'(?(a.))', "bad character in group name 'a.'", 3)
        # New valid/invalid identifiers in Python 3
        re.compile('(?P<µ>x)(?P=µ)(?(µ)y)')
        re.compile('(?P<𝔘𝔫𝔦𝔠𝔬𝔡𝔢>x)(?P=𝔘𝔫𝔦𝔠𝔬𝔡𝔢)(?(𝔘𝔫𝔦𝔠𝔬𝔡𝔢)y)')
        self.checkPatternError('(?P<©>x)', "bad character in group name '©'", 4)
        # Support > 100 groups.
        pat = '|'.join('x(?P<a%d>%x)y' % (i, i) for i in range(1, 200 + 1))
        pat = '(?:%s)(?(200)z|t)' % pat
        self.assertEqual(re.match(pat, 'xc8yz').span(), (0, 5))

    def test_symbolic_refs(self):
        self.checkTemplateError('(?P<a>x)', r'\g<a', 'xx',
                                'missing >, unterminated name', 3)
        self.checkTemplateError('(?P<a>x)', r'\g<', 'xx',
                                'missing group name', 3)
        self.checkTemplateError('(?P<a>x)', r'\g', 'xx', 'missing <', 2)
        self.checkTemplateError('(?P<a>x)', r'\g<a a>', 'xx',
                                "bad character in group name 'a a'", 3)
        self.checkTemplateError('(?P<a>x)', r'\g<>', 'xx',
                                'missing group name', 3)
        self.checkTemplateError('(?P<a>x)', r'\g<1a1>', 'xx',
                                "bad character in group name '1a1'", 3)
        self.checkTemplateError('(?P<a>x)', r'\g<2>', 'xx',
                                'invalid group reference 2', 3)
        self.checkTemplateError('(?P<a>x)', r'\2', 'xx',
                                'invalid group reference 2', 1)
        with self.assertRaisesRegex(IndexError, "unknown group name 'ab'"):
            re.sub('(?P<a>x)', r'\g<ab>', 'xx')
        self.assertEqual(re.sub('(?P<a>x)|(?P<b>y)', r'\g<b>', 'xx'), '')
        self.assertEqual(re.sub('(?P<a>x)|(?P<b>y)', r'\2', 'xx'), '')
        self.checkTemplateError('(?P<a>x)', r'\g<-1>', 'xx',
                                "bad character in group name '-1'", 3)
        # New valid/invalid identifiers in Python 3
        self.assertEqual(re.sub('(?P<µ>x)', r'\g<µ>', 'xx'), 'xx')
        self.assertEqual(re.sub('(?P<𝔘𝔫𝔦𝔠𝔬𝔡𝔢>x)', r'\g<𝔘𝔫𝔦𝔠𝔬𝔡𝔢>', 'xx'), 'xx')
        self.checkTemplateError('(?P<a>x)', r'\g<©>', 'xx',
                                "bad character in group name '©'", 3)
        # Support > 100 groups.
        pat = '|'.join('x(?P<a%d>%x)y' % (i, i) for i in range(1, 200 + 1))
        self.assertEqual(re.sub(pat, r'\g<200>', 'xc8yzxc8y'), 'c8zc8')

    def test_re_subn(self):
        self.assertEqual(re.subn("(?i)b+", "x", "bbbb BBBB"), ('x x', 2))
        self.assertEqual(re.subn("b+", "x", "bbbb BBBB"), ('x BBBB', 1))
        self.assertEqual(re.subn("b+", "x", "xyz"), ('xyz', 0))
        self.assertEqual(re.subn("b*", "x", "xyz"), ('xxxyxzx', 4))
        self.assertEqual(re.subn("b*", "x", "xyz", 2), ('xxxyz', 2))
        self.assertEqual(re.subn("b*", "x", "xyz", count=2), ('xxxyz', 2))

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_re_split(self):
        for string in ":a:b::c", S(":a:b::c"):
            self.assertTypedEqual(re.split(":", string),
                                  ['', 'a', 'b', '', 'c'])
            self.assertTypedEqual(re.split(":+", string),
                                  ['', 'a', 'b', 'c'])
            self.assertTypedEqual(re.split("(:+)", string),
                                  ['', ':', 'a', ':', 'b', '::', 'c'])
        for string in (b":a:b::c", B(b":a:b::c"), bytearray(b":a:b::c"),
                       memoryview(b":a:b::c")):
            self.assertTypedEqual(re.split(b":", string),
                                  [b'', b'a', b'b', b'', b'c'])
            self.assertTypedEqual(re.split(b":+", string),
                                  [b'', b'a', b'b', b'c'])
            self.assertTypedEqual(re.split(b"(:+)", string),
                                  [b'', b':', b'a', b':', b'b', b'::', b'c'])
        for a, b, c in ("\xe0\xdf\xe7", "\u0430\u0431\u0432",
                        "\U0001d49c\U0001d49e\U0001d4b5"):
            string = ":%s:%s::%s" % (a, b, c)
            self.assertEqual(re.split(":", string), ['', a, b, '', c])
            self.assertEqual(re.split(":+", string), ['', a, b, c])
            self.assertEqual(re.split("(:+)", string),
                             ['', ':', a, ':', b, '::', c])

        self.assertEqual(re.split("(?::+)", ":a:b::c"), ['', 'a', 'b', 'c'])
        self.assertEqual(re.split("(:)+", ":a:b::c"),
                         ['', ':', 'a', ':', 'b', ':', 'c'])
        self.assertEqual(re.split("([b:]+)", ":a:b::c"),
                         ['', ':', 'a', ':b::', 'c'])
        self.assertEqual(re.split("(b)|(:+)", ":a:b::c"),
                         ['', None, ':', 'a', None, ':', '', 'b', None, '',
                          None, '::', 'c'])
        self.assertEqual(re.split("(?:b)|(?::+)", ":a:b::c"),
                         ['', 'a', '', '', 'c'])

        for sep, expected in [
            (':*', ['', '', 'a', '', 'b', '', 'c', '']),
            ('(?::*)', ['', '', 'a', '', 'b', '', 'c', '']),
            ('(:*)', ['', ':', '', '', 'a', ':', '', '', 'b', '::', '', '', 'c', '', '']),
            ('(:)*', ['', ':', '', None, 'a', ':', '', None, 'b', ':', '', None, 'c', None, '']),
        ]:
            with self.subTest(sep=sep):
                self.assertTypedEqual(re.split(sep, ':a:b::c'), expected)

        for sep, expected in [
            ('', ['', ':', 'a', ':', 'b', ':', ':', 'c', '']),
            (r'\b', [':', 'a', ':', 'b', '::', 'c', '']),
            (r'(?=:)', ['', ':a', ':b', ':', ':c']),
            (r'(?<=:)', [':', 'a:', 'b:', ':', 'c']),
        ]:
            with self.subTest(sep=sep):
                self.assertTypedEqual(re.split(sep, ':a:b::c'), expected)

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_qualified_re_split(self):
        self.assertEqual(re.split(":", ":a:b::c", 2), ['', 'a', 'b::c'])
        self.assertEqual(re.split(":", ":a:b::c", maxsplit=2), ['', 'a', 'b::c'])
        self.assertEqual(re.split(':', 'a:b:c:d', maxsplit=2), ['a', 'b', 'c:d'])
        self.assertEqual(re.split("(:)", ":a:b::c", maxsplit=2),
                         ['', ':', 'a', ':', 'b::c'])
        self.assertEqual(re.split("(:+)", ":a:b::c", maxsplit=2),
                         ['', ':', 'a', ':', 'b::c'])
        self.assertEqual(re.split("(:*)", ":a:b::c", maxsplit=2),
                         ['', ':', '', '', 'a:b::c'])

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_re_findall(self):
        self.assertEqual(re.findall(":+", "abc"), [])
        for string in "a:b::c:::d", S("a:b::c:::d"):
            self.assertTypedEqual(re.findall(":+", string),
                                  [":", "::", ":::"])
            self.assertTypedEqual(re.findall("(:+)", string),
                                  [":", "::", ":::"])
            self.assertTypedEqual(re.findall("(:)(:*)", string),
                                  [(":", ""), (":", ":"), (":", "::")])
        for string in (b"a:b::c:::d", B(b"a:b::c:::d"), bytearray(b"a:b::c:::d"),
                       memoryview(b"a:b::c:::d")):
            self.assertTypedEqual(re.findall(b":+", string),
                                  [b":", b"::", b":::"])
            self.assertTypedEqual(re.findall(b"(:+)", string),
                                  [b":", b"::", b":::"])
            self.assertTypedEqual(re.findall(b"(:)(:*)", string),
                                  [(b":", b""), (b":", b":"), (b":", b"::")])
        for x in ("\xe0", "\u0430", "\U0001d49c"):
            xx = x * 2
            xxx = x * 3
            string = "a%sb%sc%sd" % (x, xx, xxx)
            self.assertEqual(re.findall("%s+" % x, string), [x, xx, xxx])
            self.assertEqual(re.findall("(%s+)" % x, string), [x, xx, xxx])
            self.assertEqual(re.findall("(%s)(%s*)" % (x, x), string),
                             [(x, ""), (x, x), (x, xx)])

    def test_bug_117612(self):
        self.assertEqual(re.findall(r"(a|(b))", "aba"),
                         [("a", ""),("b", "b"),("a", "")])

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_re_match(self):
        for string in 'a', S('a'):
            self.assertEqual(re.match('a', string).groups(), ())
            self.assertEqual(re.match('(a)', string).groups(), ('a',))
            self.assertEqual(re.match('(a)', string).group(0), 'a')
            self.assertEqual(re.match('(a)', string).group(1), 'a')
            self.assertEqual(re.match('(a)', string).group(1, 1), ('a', 'a'))
        for string in b'a', B(b'a'), bytearray(b'a'), memoryview(b'a'):
            self.assertEqual(re.match(b'a', string).groups(), ())
            self.assertEqual(re.match(b'(a)', string).groups(), (b'a',))
            self.assertEqual(re.match(b'(a)', string).group(0), b'a')
            self.assertEqual(re.match(b'(a)', string).group(1), b'a')
            self.assertEqual(re.match(b'(a)', string).group(1, 1), (b'a', b'a'))
        for a in ("\xe0", "\u0430", "\U0001d49c"):
            self.assertEqual(re.match(a, a).groups(), ())
            self.assertEqual(re.match('(%s)' % a, a).groups(), (a,))
            self.assertEqual(re.match('(%s)' % a, a).group(0), a)
            self.assertEqual(re.match('(%s)' % a, a).group(1), a)
            self.assertEqual(re.match('(%s)' % a, a).group(1, 1), (a, a))

        pat = re.compile('((a)|(b))(c)?')
        self.assertEqual(pat.match('a').groups(), ('a', 'a', None, None))
        self.assertEqual(pat.match('b').groups(), ('b', None, 'b', None))
        self.assertEqual(pat.match('ac').groups(), ('a', 'a', None, 'c'))
        self.assertEqual(pat.match('bc').groups(), ('b', None, 'b', 'c'))
        self.assertEqual(pat.match('bc').groups(""), ('b', "", 'b', 'c'))

        pat = re.compile('(?:(?P<a1>a)|(?P<b2>b))(?P<c3>c)?')
        self.assertEqual(pat.match('a').group(1, 2, 3), ('a', None, None))
        self.assertEqual(pat.match('b').group('a1', 'b2', 'c3'),
                         (None, 'b', None))
        self.assertEqual(pat.match('ac').group(1, 'b2', 3), ('a', None, 'c'))

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_group(self):
        class Index:
            def __init__(self, value):
                self.value = value
            def __index__(self):
                return self.value
        # A single group
        m = re.match('(a)(b)', 'ab')
        self.assertEqual(m.group(), 'ab')
        self.assertEqual(m.group(0), 'ab')
        self.assertEqual(m.group(1), 'a')
        self.assertEqual(m.group(Index(1)), 'a')
        self.assertRaises(IndexError, m.group, -1)
        self.assertRaises(IndexError, m.group, 3)
        self.assertRaises(IndexError, m.group, 1<<1000)
        self.assertRaises(IndexError, m.group, Index(1<<1000))
        self.assertRaises(IndexError, m.group, 'x')
        # Multiple groups
        self.assertEqual(m.group(2, 1), ('b', 'a'))
        self.assertEqual(m.group(Index(2), Index(1)), ('b', 'a'))

    def test_match_getitem(self):
        pat = re.compile('(?:(?P<a1>a)|(?P<b2>b))(?P<c3>c)?')

        m = pat.match('a')
        self.assertEqual(m['a1'], 'a')
        self.assertEqual(m['b2'], None)
        self.assertEqual(m['c3'], None)
        self.assertEqual('a1={a1} b2={b2} c3={c3}'.format_map(m), 'a1=a b2=None c3=None')
        self.assertEqual(m[0], 'a')
        self.assertEqual(m[1], 'a')
        self.assertEqual(m[2], None)
        self.assertEqual(m[3], None)
        with self.assertRaisesRegex(IndexError, 'no such group'):
            m['X']
        with self.assertRaisesRegex(IndexError, 'no such group'):
            m[-1]
        with self.assertRaisesRegex(IndexError, 'no such group'):
            m[4]
        with self.assertRaisesRegex(IndexError, 'no such group'):
            m[0, 1]
        with self.assertRaisesRegex(IndexError, 'no such group'):
            m[(0,)]
        with self.assertRaisesRegex(IndexError, 'no such group'):
            m[(0, 1)]
        with self.assertRaisesRegex(IndexError, 'no such group'):
            'a1={a2}'.format_map(m)

        m = pat.match('ac')
        self.assertEqual(m['a1'], 'a')
        self.assertEqual(m['b2'], None)
        self.assertEqual(m['c3'], 'c')
        self.assertEqual('a1={a1} b2={b2} c3={c3}'.format_map(m), 'a1=a b2=None c3=c')
        self.assertEqual(m[0], 'ac')
        self.assertEqual(m[1], 'a')
        self.assertEqual(m[2], None)
        self.assertEqual(m[3], 'c')

        # Cannot assign.
        with self.assertRaises(TypeError):
            m[0] = 1

        # No len().
        self.assertRaises(TypeError, len, m)

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_re_fullmatch(self):
        # Issue 16203: Proposal: add re.fullmatch() method.
        self.assertEqual(re.fullmatch(r"a", "a").span(), (0, 1))
        for string in "ab", S("ab"):
            self.assertEqual(re.fullmatch(r"a|ab", string).span(), (0, 2))
        for string in b"ab", B(b"ab"), bytearray(b"ab"), memoryview(b"ab"):
            self.assertEqual(re.fullmatch(br"a|ab", string).span(), (0, 2))
        for a, b in "\xe0\xdf", "\u0430\u0431", "\U0001d49c\U0001d49e":
            r = r"%s|%s" % (a, a + b)
            self.assertEqual(re.fullmatch(r, a + b).span(), (0, 2))
        self.assertEqual(re.fullmatch(r".*?$", "abc").span(), (0, 3))
        self.assertEqual(re.fullmatch(r".*?", "abc").span(), (0, 3))
        self.assertEqual(re.fullmatch(r"a.*?b", "ab").span(), (0, 2))
        self.assertEqual(re.fullmatch(r"a.*?b", "abb").span(), (0, 3))
        self.assertEqual(re.fullmatch(r"a.*?b", "axxb").span(), (0, 4))
        self.assertIsNone(re.fullmatch(r"a+", "ab"))
        self.assertIsNone(re.fullmatch(r"abc$", "abc\n"))
        self.assertIsNone(re.fullmatch(r"abc\Z", "abc\n"))
        self.assertIsNone(re.fullmatch(r"(?m)abc$", "abc\n"))
        self.assertEqual(re.fullmatch(r"ab(?=c)cd", "abcd").span(), (0, 4))
        self.assertEqual(re.fullmatch(r"ab(?<=b)cd", "abcd").span(), (0, 4))
        self.assertEqual(re.fullmatch(r"(?=a|ab)ab", "ab").span(), (0, 2))

        self.assertEqual(
            re.compile(r"bc").fullmatch("abcd", pos=1, endpos=3).span(), (1, 3))
        self.assertEqual(
            re.compile(r".*?$").fullmatch("abcd", pos=1, endpos=3).span(), (1, 3))
        self.assertEqual(
            re.compile(r".*?").fullmatch("abcd", pos=1, endpos=3).span(), (1, 3))

    def test_re_groupref_exists(self):
        self.assertEqual(re.match(r'^(\()?([^()]+)(?(1)\))$', '(a)').groups(),
                         ('(', 'a'))
        self.assertEqual(re.match(r'^(\()?([^()]+)(?(1)\))$', 'a').groups(),
                         (None, 'a'))
        self.assertIsNone(re.match(r'^(\()?([^()]+)(?(1)\))$', 'a)'))
        self.assertIsNone(re.match(r'^(\()?([^()]+)(?(1)\))$', '(a'))
        self.assertEqual(re.match('^(?:(a)|c)((?(1)b|d))$', 'ab').groups(),
                         ('a', 'b'))
        self.assertEqual(re.match(r'^(?:(a)|c)((?(1)b|d))$', 'cd').groups(),
                         (None, 'd'))
        self.assertEqual(re.match(r'^(?:(a)|c)((?(1)|d))$', 'cd').groups(),
                         (None, 'd'))
        self.assertEqual(re.match(r'^(?:(a)|c)((?(1)|d))$', 'a').groups(),
                         ('a', ''))

        # Tests for bug #1177831: exercise groups other than the first group
        p = re.compile('(?P<g1>a)(?P<g2>b)?((?(g2)c|d))')
        self.assertEqual(p.match('abc').groups(),
                         ('a', 'b', 'c'))
        self.assertEqual(p.match('ad').groups(),
                         ('a', None, 'd'))
        self.assertIsNone(p.match('abd'))
        self.assertIsNone(p.match('ac'))

        # Support > 100 groups.
        pat = '|'.join('x(?P<a%d>%x)y' % (i, i) for i in range(1, 200 + 1))
        pat = '(?:%s)(?(200)z)' % pat
        self.assertEqual(re.match(pat, 'xc8yz').span(), (0, 5))

        self.checkPatternError(r'(?P<a>)(?(0))', 'bad group number', 10)
        self.checkPatternError(r'()(?(1)a|b',
                               'missing ), unterminated subpattern', 2)
        self.checkPatternError(r'()(?(1)a|b|c)',
                               'conditional backref with more than '
                               'two branches', 10)

    def test_re_groupref_overflow(self):
        from sre_constants import MAXGROUPS
        self.checkTemplateError('()', r'\g<%s>' % MAXGROUPS, 'xx',
                                'invalid group reference %d' % MAXGROUPS, 3)
        self.checkPatternError(r'(?P<a>)(?(%d))' % MAXGROUPS,
                               'invalid group reference %d' % MAXGROUPS, 10)

    def test_re_groupref(self):
        self.assertEqual(re.match(r'^(\|)?([^()]+)\1$', '|a|').groups(),
                         ('|', 'a'))
        self.assertEqual(re.match(r'^(\|)?([^()]+)\1?$', 'a').groups(),
                         (None, 'a'))
        self.assertIsNone(re.match(r'^(\|)?([^()]+)\1$', 'a|'))
        self.assertIsNone(re.match(r'^(\|)?([^()]+)\1$', '|a'))
        self.assertEqual(re.match(r'^(?:(a)|c)(\1)$', 'aa').groups(),
                         ('a', 'a'))
        self.assertEqual(re.match(r'^(?:(a)|c)(\1)?$', 'c').groups(),
                         (None, None))

        self.checkPatternError(r'(abc\1)', 'cannot refer to an open group', 4)

    def test_groupdict(self):
        self.assertEqual(re.match('(?P<first>first) (?P<second>second)',
                                  'first second').groupdict(),
                         {'first':'first', 'second':'second'})

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_expand(self):
        self.assertEqual(re.match("(?P<first>first) (?P<second>second)",
                                  "first second")
                                  .expand(r"\2 \1 \g<second> \g<first>"),
                         "second first second first")
        self.assertEqual(re.match("(?P<first>first)|(?P<second>second)",
                                  "first")
                                  .expand(r"\2 \g<second>"),
                         " ")

    def test_repeat_minmax(self):
        self.assertIsNone(re.match(r"^(\w){1}$", "abc"))
        self.assertIsNone(re.match(r"^(\w){1}?$", "abc"))
        self.assertIsNone(re.match(r"^(\w){1,2}$", "abc"))
        self.assertIsNone(re.match(r"^(\w){1,2}?$", "abc"))

        self.assertEqual(re.match(r"^(\w){3}$", "abc").group(1), "c")
        self.assertEqual(re.match(r"^(\w){1,3}$", "abc").group(1), "c")
        self.assertEqual(re.match(r"^(\w){1,4}$", "abc").group(1), "c")
        self.assertEqual(re.match(r"^(\w){3,4}?$", "abc").group(1), "c")
        self.assertEqual(re.match(r"^(\w){3}?$", "abc").group(1), "c")
        self.assertEqual(re.match(r"^(\w){1,3}?$", "abc").group(1), "c")
        self.assertEqual(re.match(r"^(\w){1,4}?$", "abc").group(1), "c")
        self.assertEqual(re.match(r"^(\w){3,4}?$", "abc").group(1), "c")

        self.assertIsNone(re.match(r"^x{1}$", "xxx"))
        self.assertIsNone(re.match(r"^x{1}?$", "xxx"))
        self.assertIsNone(re.match(r"^x{1,2}$", "xxx"))
        self.assertIsNone(re.match(r"^x{1,2}?$", "xxx"))

        self.assertTrue(re.match(r"^x{3}$", "xxx"))
        self.assertTrue(re.match(r"^x{1,3}$", "xxx"))
        self.assertTrue(re.match(r"^x{3,3}$", "xxx"))
        self.assertTrue(re.match(r"^x{1,4}$", "xxx"))
        self.assertTrue(re.match(r"^x{3,4}?$", "xxx"))
        self.assertTrue(re.match(r"^x{3}?$", "xxx"))
        self.assertTrue(re.match(r"^x{1,3}?$", "xxx"))
        self.assertTrue(re.match(r"^x{1,4}?$", "xxx"))
        self.assertTrue(re.match(r"^x{3,4}?$", "xxx"))

        self.assertIsNone(re.match(r"^x{}$", "xxx"))
        self.assertTrue(re.match(r"^x{}$", "x{}"))

        self.checkPatternError(r'x{2,1}',
                               'min repeat greater than max repeat', 2)

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_getattr(self):
        self.assertEqual(re.compile("(?i)(a)(b)").pattern, "(?i)(a)(b)")
        self.assertEqual(re.compile("(?i)(a)(b)").flags, re.I | re.U)
        self.assertEqual(re.compile("(?i)(a)(b)").groups, 2)
        self.assertEqual(re.compile("(?i)(a)(b)").groupindex, {})
        self.assertEqual(re.compile("(?i)(?P<first>a)(?P<other>b)").groupindex,
                         {'first': 1, 'other': 2})

        self.assertEqual(re.match("(a)", "a").pos, 0)
        self.assertEqual(re.match("(a)", "a").endpos, 1)
        self.assertEqual(re.match("(a)", "a").string, "a")
        self.assertEqual(re.match("(a)", "a").regs, ((0, 1), (0, 1)))
        self.assertTrue(re.match("(a)", "a").re)

        # Issue 14260. groupindex should be non-modifiable mapping.
        p = re.compile(r'(?i)(?P<first>a)(?P<other>b)')
        self.assertEqual(sorted(p.groupindex), ['first', 'other'])
        self.assertEqual(p.groupindex['other'], 2)
        with self.assertRaises(TypeError):
            p.groupindex['other'] = 0
        self.assertEqual(p.groupindex['other'], 2)

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_special_escapes(self):
        self.assertEqual(re.search(r"\b(b.)\b",
                                   "abcd abc bcd bx").group(1), "bx")
        self.assertEqual(re.search(r"\B(b.)\B",
                                   "abc bcd bc abxd").group(1), "bx")
        self.assertEqual(re.search(r"\b(b.)\b",
                                   "abcd abc bcd bx", re.ASCII).group(1), "bx")
        self.assertEqual(re.search(r"\B(b.)\B",
                                   "abc bcd bc abxd", re.ASCII).group(1), "bx")
        self.assertEqual(re.search(r"^abc$", "\nabc\n", re.M).group(0), "abc")
        self.assertEqual(re.search(r"^\Aabc\Z$", "abc", re.M).group(0), "abc")
        self.assertIsNone(re.search(r"^\Aabc\Z$", "\nabc\n", re.M))
        self.assertEqual(re.search(br"\b(b.)\b",
                                   b"abcd abc bcd bx").group(1), b"bx")
        self.assertEqual(re.search(br"\B(b.)\B",
                                   b"abc bcd bc abxd").group(1), b"bx")
        self.assertEqual(re.search(br"\b(b.)\b",
                                   b"abcd abc bcd bx", re.LOCALE).group(1), b"bx")
        self.assertEqual(re.search(br"\B(b.)\B",
                                   b"abc bcd bc abxd", re.LOCALE).group(1), b"bx")
        self.assertEqual(re.search(br"^abc$", b"\nabc\n", re.M).group(0), b"abc")
        self.assertEqual(re.search(br"^\Aabc\Z$", b"abc", re.M).group(0), b"abc")
        self.assertIsNone(re.search(br"^\Aabc\Z$", b"\nabc\n", re.M))
        self.assertEqual(re.search(r"\d\D\w\W\s\S",
                                   "1aa! a").group(0), "1aa! a")
        self.assertEqual(re.search(br"\d\D\w\W\s\S",
                                   b"1aa! a").group(0), b"1aa! a")
        self.assertEqual(re.search(r"\d\D\w\W\s\S",
                                   "1aa! a", re.ASCII).group(0), "1aa! a")
        self.assertEqual(re.search(br"\d\D\w\W\s\S",
                                   b"1aa! a", re.LOCALE).group(0), b"1aa! a")

    def test_other_escapes(self):
        self.checkPatternError("\\", 'bad escape (end of pattern)', 0)
        self.assertEqual(re.match(r"\(", '(').group(), '(')
        self.assertIsNone(re.match(r"\(", ')'))
        self.assertEqual(re.match(r"\\", '\\').group(), '\\')
        self.assertEqual(re.match(r"[\]]", ']').group(), ']')
        self.assertIsNone(re.match(r"[\]]", '['))
        self.assertEqual(re.match(r"[a\-c]", '-').group(), '-')
        self.assertIsNone(re.match(r"[a\-c]", 'b'))
        self.assertEqual(re.match(r"[\^a]+", 'a^').group(), 'a^')
        self.assertIsNone(re.match(r"[\^a]+", 'b'))
        re.purge()  # for warnings
        for c in 'ceghijklmopqyzCEFGHIJKLMNOPQRTVXY':
            with self.subTest(c):
                self.assertRaises(re.error, re.compile, '\\%c' % c)
        for c in 'ceghijklmopqyzABCEFGHIJKLMNOPQRTVXYZ':
            with self.subTest(c):
                self.assertRaises(re.error, re.compile, '[\\%c]' % c)

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_named_unicode_escapes(self):
        # test individual Unicode named escapes
        self.assertTrue(re.match(r'\N{LESS-THAN SIGN}', '<'))
        self.assertTrue(re.match(r'\N{less-than sign}', '<'))
        self.assertIsNone(re.match(r'\N{LESS-THAN SIGN}', '>'))
        self.assertTrue(re.match(r'\N{SNAKE}', '\U0001f40d'))
        self.assertTrue(re.match(r'\N{ARABIC LIGATURE UIGHUR KIRGHIZ YEH WITH '
                                 r'HAMZA ABOVE WITH ALEF MAKSURA ISOLATED FORM}',
                                 '\ufbf9'))
        self.assertTrue(re.match(r'[\N{LESS-THAN SIGN}-\N{GREATER-THAN SIGN}]',
                                 '='))
        self.assertIsNone(re.match(r'[\N{LESS-THAN SIGN}-\N{GREATER-THAN SIGN}]',
                                   ';'))

        # test errors in \N{name} handling - only valid names should pass
        self.checkPatternError(r'\N', 'missing {', 2)
        self.checkPatternError(r'[\N]', 'missing {', 3)
        self.checkPatternError(r'\N{', 'missing character name', 3)
        self.checkPatternError(r'[\N{', 'missing character name', 4)
        self.checkPatternError(r'\N{}', 'missing character name', 3)
        self.checkPatternError(r'[\N{}]', 'missing character name', 4)
        self.checkPatternError(r'\NSNAKE}', 'missing {', 2)
        self.checkPatternError(r'[\NSNAKE}]', 'missing {', 3)
        self.checkPatternError(r'\N{SNAKE',
                               'missing }, unterminated name', 3)
        self.checkPatternError(r'[\N{SNAKE]',
                               'missing }, unterminated name', 4)
        self.checkPatternError(r'[\N{SNAKE]}',
                               "undefined character name 'SNAKE]'", 1)
        self.checkPatternError(r'\N{SPAM}',
                               "undefined character name 'SPAM'", 0)
        self.checkPatternError(r'[\N{SPAM}]',
                               "undefined character name 'SPAM'", 1)
        self.checkPatternError(br'\N{LESS-THAN SIGN}', r'bad escape \N', 0)
        self.checkPatternError(br'[\N{LESS-THAN SIGN}]', r'bad escape \N', 1)

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_string_boundaries(self):
        # See http://bugs.python.org/issue10713
        self.assertEqual(re.search(r"\b(abc)\b", "abc").group(1),
                         "abc")
        # There's a word boundary at the start of a string.
        self.assertTrue(re.match(r"\b", "abc"))
        # A non-empty string includes a non-boundary zero-length match.
        self.assertTrue(re.search(r"\B", "abc"))
        # There is no non-boundary match at the start of a string.
        self.assertFalse(re.match(r"\B", "abc"))
        # However, an empty string contains no word boundaries, and also no
        # non-boundaries.
        self.assertIsNone(re.search(r"\B", ""))
        # This one is questionable and different from the perlre behaviour,
        # but describes current behavior.
        self.assertIsNone(re.search(r"\b", ""))
        # A single word-character string has two boundaries, but no
        # non-boundary gaps.
        self.assertEqual(len(re.findall(r"\b", "a")), 2)
        self.assertEqual(len(re.findall(r"\B", "a")), 0)
        # If there are no words, there are no boundaries
        self.assertEqual(len(re.findall(r"\b", " ")), 0)
        self.assertEqual(len(re.findall(r"\b", "   ")), 0)
        # Can match around the whitespace.
        self.assertEqual(len(re.findall(r"\B", " ")), 2)

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_bigcharset(self):
        self.assertEqual(re.match("([\u2222\u2223])",
                                  "\u2222").group(1), "\u2222")
        r = '[%s]' % ''.join(map(chr, range(256, 2**16, 255)))
        self.assertEqual(re.match(r, "\uff01").group(), "\uff01")

    def test_big_codesize(self):
        # Issue #1160
        r = re.compile('|'.join(('%d'%x for x in range(10000))))
        self.assertTrue(r.match('1000'))
        self.assertTrue(r.match('9999'))

    def test_anyall(self):
        self.assertEqual(re.match("a.b", "a\nb", re.DOTALL).group(0),
                         "a\nb")
        self.assertEqual(re.match("a.*b", "a\n\nb", re.DOTALL).group(0),
                         "a\n\nb")

    def test_lookahead(self):
        self.assertEqual(re.match(r"(a(?=\s[^a]))", "a b").group(1), "a")
        self.assertEqual(re.match(r"(a(?=\s[^a]*))", "a b").group(1), "a")
        self.assertEqual(re.match(r"(a(?=\s[abc]))", "a b").group(1), "a")
        self.assertEqual(re.match(r"(a(?=\s[abc]*))", "a bc").group(1), "a")
        self.assertEqual(re.match(r"(a)(?=\s\1)", "a a").group(1), "a")
        self.assertEqual(re.match(r"(a)(?=\s\1*)", "a aa").group(1), "a")
        self.assertEqual(re.match(r"(a)(?=\s(abc|a))", "a a").group(1), "a")

        self.assertEqual(re.match(r"(a(?!\s[^a]))", "a a").group(1), "a")
        self.assertEqual(re.match(r"(a(?!\s[abc]))", "a d").group(1), "a")
        self.assertEqual(re.match(r"(a)(?!\s\1)", "a b").group(1), "a")
        self.assertEqual(re.match(r"(a)(?!\s(abc|a))", "a b").group(1), "a")

        # Group reference.
        self.assertTrue(re.match(r'(a)b(?=\1)a', 'aba'))
        self.assertIsNone(re.match(r'(a)b(?=\1)c', 'abac'))
        # Conditional group reference.
        self.assertTrue(re.match(r'(?:(a)|(x))b(?=(?(2)x|c))c', 'abc'))
        self.assertIsNone(re.match(r'(?:(a)|(x))b(?=(?(2)c|x))c', 'abc'))
        self.assertTrue(re.match(r'(?:(a)|(x))b(?=(?(2)x|c))c', 'abc'))
        self.assertIsNone(re.match(r'(?:(a)|(x))b(?=(?(1)b|x))c', 'abc'))
        self.assertTrue(re.match(r'(?:(a)|(x))b(?=(?(1)c|x))c', 'abc'))
        # Group used before defined.
        self.assertTrue(re.match(r'(a)b(?=(?(2)x|c))(c)', 'abc'))
        self.assertIsNone(re.match(r'(a)b(?=(?(2)b|x))(c)', 'abc'))
        self.assertTrue(re.match(r'(a)b(?=(?(1)c|x))(c)', 'abc'))

    def test_lookbehind(self):
        self.assertTrue(re.match(r'ab(?<=b)c', 'abc'))
        self.assertIsNone(re.match(r'ab(?<=c)c', 'abc'))
        self.assertIsNone(re.match(r'ab(?<!b)c', 'abc'))
        self.assertTrue(re.match(r'ab(?<!c)c', 'abc'))
        # Group reference.
        self.assertTrue(re.match(r'(a)a(?<=\1)c', 'aac'))
        self.assertIsNone(re.match(r'(a)b(?<=\1)a', 'abaa'))
        self.assertIsNone(re.match(r'(a)a(?<!\1)c', 'aac'))
        self.assertTrue(re.match(r'(a)b(?<!\1)a', 'abaa'))
        # Conditional group reference.
        self.assertIsNone(re.match(r'(?:(a)|(x))b(?<=(?(2)x|c))c', 'abc'))
        self.assertIsNone(re.match(r'(?:(a)|(x))b(?<=(?(2)b|x))c', 'abc'))
        self.assertTrue(re.match(r'(?:(a)|(x))b(?<=(?(2)x|b))c', 'abc'))
        self.assertIsNone(re.match(r'(?:(a)|(x))b(?<=(?(1)c|x))c', 'abc'))
        self.assertTrue(re.match(r'(?:(a)|(x))b(?<=(?(1)b|x))c', 'abc'))
        # Group used before defined.
        self.assertRaises(re.error, re.compile, r'(a)b(?<=(?(2)b|x))(c)')
        self.assertIsNone(re.match(r'(a)b(?<=(?(1)c|x))(c)', 'abc'))
        self.assertTrue(re.match(r'(a)b(?<=(?(1)b|x))(c)', 'abc'))
        # Group defined in the same lookbehind pattern
        self.assertRaises(re.error, re.compile, r'(a)b(?<=(.)\2)(c)')
        self.assertRaises(re.error, re.compile, r'(a)b(?<=(?P<a>.)(?P=a))(c)')
        self.assertRaises(re.error, re.compile, r'(a)b(?<=(a)(?(2)b|x))(c)')
        self.assertRaises(re.error, re.compile, r'(a)b(?<=(.)(?<=\2))(c)')

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_ignore_case(self):
        self.assertEqual(re.match("abc", "ABC", re.I).group(0), "ABC")
        self.assertEqual(re.match(b"abc", b"ABC", re.I).group(0), b"ABC")
        self.assertEqual(re.match(r"(a\s[^a])", "a b", re.I).group(1), "a b")
        self.assertEqual(re.match(r"(a\s[^a]*)", "a bb", re.I).group(1), "a bb")
        self.assertEqual(re.match(r"(a\s[abc])", "a b", re.I).group(1), "a b")
        self.assertEqual(re.match(r"(a\s[abc]*)", "a bb", re.I).group(1), "a bb")
        self.assertEqual(re.match(r"((a)\s\2)", "a a", re.I).group(1), "a a")
        self.assertEqual(re.match(r"((a)\s\2*)", "a aa", re.I).group(1), "a aa")
        self.assertEqual(re.match(r"((a)\s(abc|a))", "a a", re.I).group(1), "a a")
        self.assertEqual(re.match(r"((a)\s(abc|a)*)", "a aa", re.I).group(1), "a aa")

        assert '\u212a'.lower() == 'k' # 'K'
        self.assertTrue(re.match(r'K', '\u212a', re.I))
        self.assertTrue(re.match(r'k', '\u212a', re.I))
        self.assertTrue(re.match(r'\u212a', 'K', re.I))
        self.assertTrue(re.match(r'\u212a', 'k', re.I))
        assert '\u017f'.upper() == 'S' # 'ſ'
        self.assertTrue(re.match(r'S', '\u017f', re.I))
        self.assertTrue(re.match(r's', '\u017f', re.I))
        self.assertTrue(re.match(r'\u017f', 'S', re.I))
        self.assertTrue(re.match(r'\u017f', 's', re.I))
        assert '\ufb05'.upper() == '\ufb06'.upper() == 'ST' # 'ſt', 'st'
        self.assertTrue(re.match(r'\ufb05', '\ufb06', re.I))
        self.assertTrue(re.match(r'\ufb06', '\ufb05', re.I))

    def test_ignore_case_set(self):
        self.assertTrue(re.match(r'[19A]', 'A', re.I))
        self.assertTrue(re.match(r'[19a]', 'a', re.I))
        self.assertTrue(re.match(r'[19a]', 'A', re.I))
        self.assertTrue(re.match(r'[19A]', 'a', re.I))
        self.assertTrue(re.match(br'[19A]', b'A', re.I))
        self.assertTrue(re.match(br'[19a]', b'a', re.I))
        self.assertTrue(re.match(br'[19a]', b'A', re.I))
        self.assertTrue(re.match(br'[19A]', b'a', re.I))
        assert '\u212a'.lower() == 'k' # 'K'
        self.assertTrue(re.match(r'[19K]', '\u212a', re.I))
        self.assertTrue(re.match(r'[19k]', '\u212a', re.I))
        self.assertTrue(re.match(r'[19\u212a]', 'K', re.I))
        self.assertTrue(re.match(r'[19\u212a]', 'k', re.I))
        assert '\u017f'.upper() == 'S' # 'ſ'
        self.assertTrue(re.match(r'[19S]', '\u017f', re.I))
        self.assertTrue(re.match(r'[19s]', '\u017f', re.I))
        self.assertTrue(re.match(r'[19\u017f]', 'S', re.I))
        self.assertTrue(re.match(r'[19\u017f]', 's', re.I))
        assert '\ufb05'.upper() == '\ufb06'.upper() == 'ST' # 'ſt', 'st'
        self.assertTrue(re.match(r'[19\ufb05]', '\ufb06', re.I))
        self.assertTrue(re.match(r'[19\ufb06]', '\ufb05', re.I))

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_ignore_case_range(self):
        # Issues #3511, #17381.
        self.assertTrue(re.match(r'[9-a]', '_', re.I))
        self.assertIsNone(re.match(r'[9-A]', '_', re.I))
        self.assertTrue(re.match(br'[9-a]', b'_', re.I))
        self.assertIsNone(re.match(br'[9-A]', b'_', re.I))
        self.assertTrue(re.match(r'[\xc0-\xde]', '\xd7', re.I))
        self.assertIsNone(re.match(r'[\xc0-\xde]', '\xf7', re.I))
        self.assertTrue(re.match(r'[\xe0-\xfe]', '\xf7', re.I))
        self.assertIsNone(re.match(r'[\xe0-\xfe]', '\xd7', re.I))
        self.assertTrue(re.match(r'[\u0430-\u045f]', '\u0450', re.I))
        self.assertTrue(re.match(r'[\u0430-\u045f]', '\u0400', re.I))
        self.assertTrue(re.match(r'[\u0400-\u042f]', '\u0450', re.I))
        self.assertTrue(re.match(r'[\u0400-\u042f]', '\u0400', re.I))
        self.assertTrue(re.match(r'[\U00010428-\U0001044f]', '\U00010428', re.I))
        self.assertTrue(re.match(r'[\U00010428-\U0001044f]', '\U00010400', re.I))
        self.assertTrue(re.match(r'[\U00010400-\U00010427]', '\U00010428', re.I))
        self.assertTrue(re.match(r'[\U00010400-\U00010427]', '\U00010400', re.I))

        assert '\u212a'.lower() == 'k' # 'K'
        self.assertTrue(re.match(r'[J-M]', '\u212a', re.I))
        self.assertTrue(re.match(r'[j-m]', '\u212a', re.I))
        self.assertTrue(re.match(r'[\u2129-\u212b]', 'K', re.I))
        self.assertTrue(re.match(r'[\u2129-\u212b]', 'k', re.I))
        assert '\u017f'.upper() == 'S' # 'ſ'
        self.assertTrue(re.match(r'[R-T]', '\u017f', re.I))
        self.assertTrue(re.match(r'[r-t]', '\u017f', re.I))
        self.assertTrue(re.match(r'[\u017e-\u0180]', 'S', re.I))
        self.assertTrue(re.match(r'[\u017e-\u0180]', 's', re.I))
        assert '\ufb05'.upper() == '\ufb06'.upper() == 'ST' # 'ſt', 'st'
        self.assertTrue(re.match(r'[\ufb04-\ufb05]', '\ufb06', re.I))
        self.assertTrue(re.match(r'[\ufb06-\ufb07]', '\ufb05', re.I))

    def test_category(self):
        self.assertEqual(re.match(r"(\s)", " ").group(1), " ")

    @cpython_only
    def test_case_helpers(self):
        import _sre
        for i in range(128):
            c = chr(i)
            lo = ord(c.lower())
            self.assertEqual(_sre.ascii_tolower(i), lo)
            self.assertEqual(_sre.unicode_tolower(i), lo)
            iscased = c in string.ascii_letters
            self.assertEqual(_sre.ascii_iscased(i), iscased)
            self.assertEqual(_sre.unicode_iscased(i), iscased)

        for i in list(range(128, 0x1000)) + [0x10400, 0x10428]:
            c = chr(i)
            self.assertEqual(_sre.ascii_tolower(i), i)
            if i != 0x0130:
                self.assertEqual(_sre.unicode_tolower(i), ord(c.lower()))
            iscased = c != c.lower() or c != c.upper()
            self.assertFalse(_sre.ascii_iscased(i))
            self.assertEqual(_sre.unicode_iscased(i),
                             c != c.lower() or c != c.upper())

        self.assertEqual(_sre.ascii_tolower(0x0130), 0x0130)
        self.assertEqual(_sre.unicode_tolower(0x0130), ord('i'))
        self.assertFalse(_sre.ascii_iscased(0x0130))
        self.assertTrue(_sre.unicode_iscased(0x0130))

    def test_not_literal(self):
        self.assertEqual(re.search(r"\s([^a])", " b").group(1), "b")
        self.assertEqual(re.search(r"\s([^a]*)", " bb").group(1), "bb")

    # TODO: RUSTPYTHON
    @unittest.expectedFailure
    def test_possible_set_operations(self):
        s = bytes(range(128)).decode()
        with self.assertWarns(FutureWarning):
            p = re.compile(r'[0-9--1]')
        self.assertEqual(p.findall(s), list('-./0123456789'))
        self.assertEqual(re.findall(r'[--1]', s), list('-./01'))
        with self.assertWarns(FutureWarning):
            p = re.compile(r'[%--1]')
        self.assertEqual(p.findall(s), list("%&'()*+,-1"))
        with self.assertWarns(FutureWarning):
            p = re.compile(r'[%--]')
        self.assertEqual(p.findall(s), list("%&'()*+,-"))

        with self.assertWarns(FutureWarning):
            p = re.compile(r'[0-9&&1]')
        self.assertEqual(p.findall(s), list('&0123456789'))
        with self.assertWarns(FutureWarning):
            p = re.compile(r'[\d&&1]')
        self.assertEqual(p.findall(s), list('&0123456789'))
        self.assertEqual(re.findall(r'[&&1]', s), list('&1'))