from weakref import proxy
import copy
import pickle
import regex
import string
import sys
import unittest

# String subclasses for issue 18468.
class StrSubclass(str):
    def __getitem__(self, index):
        return StrSubclass(super().__getitem__(index))

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

class RegexTests(unittest.TestCase):
    PATTERN_CLASS = "<class '_regex.Pattern'>"
    FLAGS_WITH_COMPILED_PAT = "cannot process flags argument with a compiled pattern"
    INVALID_GROUP_REF = "invalid group reference"
    MISSING_GT = "missing >"
    BAD_GROUP_NAME = "bad character in group name"
    MISSING_GROUP_NAME = "missing group name"
    MISSING_LT = "missing <"
    UNKNOWN_GROUP_I = "unknown group"
    UNKNOWN_GROUP = "unknown group"
    BAD_ESCAPE = r"bad escape \(end of pattern\)"
    BAD_OCTAL_ESCAPE = r"bad escape \\"
    BAD_SET = "unterminated character set"
    STR_PAT_ON_BYTES = "cannot use a string pattern on a bytes-like object"
    BYTES_PAT_ON_STR = "cannot use a bytes pattern on a string-like object"
    STR_PAT_BYTES_TEMPL = "expected str instance, bytes found"
    BYTES_PAT_STR_TEMPL = "expected a bytes-like object, str found"
    BYTES_PAT_UNI_FLAG = "cannot use UNICODE flag with a bytes pattern"
    MIXED_FLAGS = "ASCII, LOCALE and UNICODE flags are mutually incompatible"
    MISSING_RPAREN = "missing \\)"
    TRAILING_CHARS = "unbalanced parenthesis"
    BAD_CHAR_RANGE = "bad character range"
    NOTHING_TO_REPEAT = "nothing to repeat"
    MULTIPLE_REPEAT = "multiple repeat"
    OPEN_GROUP = "cannot refer to an open group"
    DUPLICATE_GROUP = "duplicate group"
    CANT_TURN_OFF = "bad inline flags: cannot turn flags off"
    UNDEF_CHAR_NAME = "undefined character name"

    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 test_weakref(self):
        s = 'QabbbcR'
        x = regex.compile('ab+c')
        y = proxy(x)
        if x.findall('QabbbcR') != y.findall('QabbbcR'):
            self.fail()

    def test_search_star_plus(self):
        self.assertEqual(regex.search('a*', 'xxx').span(0), (0, 0))
        self.assertEqual(regex.search('x*', 'axx').span(), (0, 0))
        self.assertEqual(regex.search('x+', 'axx').span(0), (1, 3))
        self.assertEqual(regex.search('x+', 'axx').span(), (1, 3))
        self.assertEqual(regex.search('x', 'aaa'), None)
        self.assertEqual(regex.match('a*', 'xxx').span(0), (0, 0))
        self.assertEqual(regex.match('a*', 'xxx').span(), (0, 0))
        self.assertEqual(regex.match('x*', 'xxxa').span(0), (0, 3))
        self.assertEqual(regex.match('x*', 'xxxa').span(), (0, 3))
        self.assertEqual(regex.match('a+', 'xxx'), None)

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

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

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

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

        self.assertEqual(regex.sub('a', r'\t\n\v\r\f\a\b', 'a'), "\t\n\v\r\f\a\b")
        self.assertEqual(regex.sub('a', '\t\n\v\r\f\a', 'a'), "\t\n\v\r\f\a")
        self.assertEqual(regex.sub('a', '\t\n\v\r\f\a', 'a'), chr(9) + chr(10)
          + chr(11) + chr(13) + chr(12) + chr(7))

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

        self.assertEqual(regex.sub(r"x", r"\x0A", "x"), "\n")
        self.assertEqual(regex.sub(r"x", r"\u000A", "x"), "\n")
        self.assertEqual(regex.sub(r"x", r"\U0000000A", "x"), "\n")
        self.assertEqual(regex.sub(r"x", r"\N{LATIN CAPITAL LETTER A}",
          "x"), "A")

        self.assertEqual(regex.sub(br"x", br"\x0A", b"x"), b"\n")

    def test_bug_449964(self):
        # Fails for group followed by other escape.
        self.assertEqual(regex.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(regex.sub(r'\r\n', r'\n', 'abc\r\ndef\r\n'),
          "abc\ndef\n")
        self.assertEqual(regex.sub('\r\n', r'\n', 'abc\r\ndef\r\n'),
          "abc\ndef\n")
        self.assertEqual(regex.sub(r'\r\n', '\n', 'abc\r\ndef\r\n'),
          "abc\ndef\n")
        self.assertEqual(regex.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 = regex.compile('.')
        self.assertRaisesRegex(ValueError, self.FLAGS_WITH_COMPILED_PAT,
          lambda: regex.match(pattern, 'A', regex.I))
        self.assertRaisesRegex(ValueError, self.FLAGS_WITH_COMPILED_PAT,
          lambda: regex.search(pattern, 'A', regex.I))
        self.assertRaisesRegex(ValueError, self.FLAGS_WITH_COMPILED_PAT,
          lambda: regex.findall(pattern, 'A', regex.I))
        self.assertRaisesRegex(ValueError, self.FLAGS_WITH_COMPILED_PAT,
          lambda: regex.compile(pattern, regex.I))

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

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

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

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

        self.assertEqual(regex.sub('x', r'\400', 'x'), "\u0100")
        self.assertEqual(regex.sub('x', r'\777', 'x'), "\u01FF")
        self.assertEqual(regex.sub(b'x', br'\400', b'x'), b"\x00")
        self.assertEqual(regex.sub(b'x', br'\777', b'x'), b"\xFF")

        self.assertRaisesRegex(regex.error, self.INVALID_GROUP_REF, lambda:
          regex.sub('x', r'\1', 'x'))
        self.assertRaisesRegex(regex.error, self.INVALID_GROUP_REF, lambda:
          regex.sub('x', r'\8', 'x'))
        self.assertRaisesRegex(regex.error, self.INVALID_GROUP_REF, lambda:
          regex.sub('x', r'\9', 'x'))
        self.assertRaisesRegex(regex.error, self.INVALID_GROUP_REF, lambda:
          regex.sub('x', r'\11', 'x'))
        self.assertRaisesRegex(regex.error, self.INVALID_GROUP_REF, lambda:
          regex.sub('x', r'\18', 'x'))
        self.assertRaisesRegex(regex.error, self.INVALID_GROUP_REF, lambda:
          regex.sub('x', r'\1a', 'x'))
        self.assertRaisesRegex(regex.error, self.INVALID_GROUP_REF, lambda:
          regex.sub('x', r'\90', 'x'))
        self.assertRaisesRegex(regex.error, self.INVALID_GROUP_REF, lambda:
          regex.sub('x', r'\99', 'x'))
        self.assertRaisesRegex(regex.error, self.INVALID_GROUP_REF, lambda:
          regex.sub('x', r'\118', 'x')) # r'\11' + '8'
        self.assertRaisesRegex(regex.error, self.INVALID_GROUP_REF, lambda:
          regex.sub('x', r'\11a', 'x'))
        self.assertRaisesRegex(regex.error, self.INVALID_GROUP_REF, lambda:
          regex.sub('x', r'\181', 'x')) # r'\18' + '1'
        self.assertRaisesRegex(regex.error, self.INVALID_GROUP_REF, lambda:
          regex.sub('x', r'\800', 'x')) # r'\80' + '0'

        # In Python 2.3 (etc), these loop endlessly in sre_parser.py.
        self.assertEqual(regex.sub('(((((((((((x)))))))))))', r'\11', 'x'),
          'x')
        self.assertEqual(regex.sub('((((((((((y))))))))))(.)', r'\118', 'xyz'),
          'xz8')
        self.assertEqual(regex.sub('((((((((((y))))))))))(.)', r'\11a', 'xyz'),
          'xza')

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

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

    def test_bug_462270(self):
        # Test for empty sub() behaviour, see SF bug #462270
        if sys.version_info >= (3, 7, 0):
            self.assertEqual(regex.sub('(?V0)x*', '-', 'abxd'), '-a-b--d-')
        else:
            self.assertEqual(regex.sub('(?V0)x*', '-', 'abxd'), '-a-b-d-')
        self.assertEqual(regex.sub('(?V1)x*', '-', 'abxd'), '-a-b--d-')
        self.assertEqual(regex.sub('x+', '-', 'abxd'), 'ab-d')

    def test_bug_14462(self):
        # chr(255) is a valid identifier in Python 3.
        group_name = '\xFF'
        self.assertEqual(regex.search(r'(?P<' + group_name + '>a)',
          'abc').group(group_name), 'a')

    def test_symbolic_refs(self):
        self.assertRaisesRegex(regex.error, self.MISSING_GT, lambda:
          regex.sub('(?P<a>x)', r'\g<a', 'xx'))
        self.assertRaisesRegex(regex.error, self.MISSING_GROUP_NAME, lambda:
          regex.sub('(?P<a>x)', r'\g<', 'xx'))
        self.assertRaisesRegex(regex.error, self.MISSING_LT, lambda:
          regex.sub('(?P<a>x)', r'\g', 'xx'))
        self.assertRaisesRegex(regex.error, self.BAD_GROUP_NAME, lambda:
          regex.sub('(?P<a>x)', r'\g<a a>', 'xx'))
        self.assertRaisesRegex(regex.error, self.BAD_GROUP_NAME, lambda:
          regex.sub('(?P<a>x)', r'\g<1a1>', 'xx'))
        self.assertRaisesRegex(IndexError, self.UNKNOWN_GROUP_I, lambda:
          regex.sub('(?P<a>x)', r'\g<ab>', 'xx'))

        # The new behaviour of unmatched but valid groups is to treat them like
        # empty matches in the replacement template, like in Perl.
        self.assertEqual(regex.sub('(?P<a>x)|(?P<b>y)', r'\g<b>', 'xx'), '')
        self.assertEqual(regex.sub('(?P<a>x)|(?P<b>y)', r'\2', 'xx'), '')

        # The old behaviour was to raise it as an IndexError.
        self.assertRaisesRegex(regex.error, self.BAD_GROUP_NAME, lambda:
          regex.sub('(?P<a>x)', r'\g<-1>', 'xx'))

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

    def test_re_split(self):
        self.assertEqual(regex.split(":", ":a:b::c"), ['', 'a', 'b', '', 'c'])
        if sys.version_info >= (3, 7, 0):
            self.assertEqual(regex.split(":*", ":a:b::c"), ['', '', 'a', '',
              'b', '', 'c', ''])
            self.assertEqual(regex.split("(:*)", ":a:b::c"), ['', ':', '', '',
              'a', ':', '', '', 'b', '::', '', '', 'c', '', ''])
            self.assertEqual(regex.split("(?::*)", ":a:b::c"), ['', '', 'a',
              '', 'b', '', 'c', ''])
            self.assertEqual(regex.split("(:)*", ":a:b::c"), ['', ':', '',
              None, 'a', ':', '', None, 'b', ':', '', None, 'c', None, ''])
        else:
            self.assertEqual(regex.split(":*", ":a:b::c"), ['', 'a', 'b', 'c'])
            self.assertEqual(regex.split("(:*)", ":a:b::c"), ['', ':', 'a',
              ':', 'b', '::', 'c'])
            self.assertEqual(regex.split("(?::*)", ":a:b::c"), ['', 'a', 'b',
              'c'])
            self.assertEqual(regex.split("(:)*", ":a:b::c"), ['', ':', 'a',
              ':', 'b', ':', 'c'])
        self.assertEqual(regex.split("([b:]+)", ":a:b::c"), ['', ':', 'a',
          ':b::', 'c'])
        self.assertEqual(regex.split("(b)|(:+)", ":a:b::c"), ['', None, ':',
          'a', None, ':', '', 'b', None, '', None, '::', 'c'])
        self.assertEqual(regex.split("(?:b)|(?::+)", ":a:b::c"), ['', 'a', '',
          '', 'c'])

        self.assertEqual(regex.split("x", "xaxbxc"), ['', 'a', 'b', 'c'])
        self.assertEqual([m for m in regex.splititer("x", "xaxbxc")], ['', 'a',
          'b', 'c'])

        self.assertEqual(regex.split("(?r)x", "xaxbxc"), ['c', 'b', 'a', ''])
        self.assertEqual([m for m in regex.splititer("(?r)x", "xaxbxc")], ['c',
          'b', 'a', ''])

        self.assertEqual(regex.split("(x)|(y)", "xaxbxc"), ['', 'x', None, 'a',
          'x', None, 'b', 'x', None, 'c'])
        self.assertEqual([m for m in regex.splititer("(x)|(y)", "xaxbxc")],
          ['', 'x', None, 'a', 'x', None, 'b', 'x', None, 'c'])

        self.assertEqual(regex.split("(?r)(x)|(y)", "xaxbxc"), ['c', 'x', None,
          'b', 'x', None, 'a', 'x', None, ''])
        self.assertEqual([m for m in regex.splititer("(?r)(x)|(y)", "xaxbxc")],
          ['c', 'x', None, 'b', 'x', None, 'a', 'x', None, ''])

        self.assertEqual(regex.split(r"(?V1)\b", "a b c"), ['', 'a', ' ', 'b',
          ' ', 'c', ''])
        self.assertEqual(regex.split(r"(?V1)\m", "a b c"), ['', 'a ', 'b ',
          'c'])
        self.assertEqual(regex.split(r"(?V1)\M", "a b c"), ['a', ' b', ' c',
          ''])

    def test_qualified_re_split(self):
        self.assertEqual(regex.split(":", ":a:b::c", 2), ['', 'a', 'b::c'])
        self.assertEqual(regex.split(':', 'a:b:c:d', 2), ['a', 'b', 'c:d'])
        self.assertEqual(regex.split("(:)", ":a:b::c", 2), ['', ':', 'a', ':',
          'b::c'])

        if sys.version_info >= (3, 7, 0):
            self.assertEqual(regex.split("(:*)", ":a:b::c", 2), ['', ':', '',
              '', 'a:b::c'])
        else:
            self.assertEqual(regex.split("(:*)", ":a:b::c", 2), ['', ':', 'a',
              ':', 'b::c'])

    def test_re_findall(self):
        self.assertEqual(regex.findall(":+", "abc"), [])
        self.assertEqual(regex.findall(":+", "a:b::c:::d"), [':', '::', ':::'])
        self.assertEqual(regex.findall("(:+)", "a:b::c:::d"), [':', '::',
          ':::'])
        self.assertEqual(regex.findall("(:)(:*)", "a:b::c:::d"), [(':', ''),
          (':', ':'), (':', '::')])

        self.assertEqual(regex.findall(r"\((?P<test>.{0,5}?TEST)\)",
          "(MY TEST)"), ["MY TEST"])
        self.assertEqual(regex.findall(r"\((?P<test>.{0,3}?TEST)\)",
          "(MY TEST)"), ["MY TEST"])
        self.assertEqual(regex.findall(r"\((?P<test>.{0,3}?T)\)", "(MY T)"),
          ["MY T"])

        self.assertEqual(regex.findall(r"[^a]{2}[A-Z]", "\n  S"), ['  S'])
        self.assertEqual(regex.findall(r"[^a]{2,3}[A-Z]", "\n  S"), ['\n  S'])
        self.assertEqual(regex.findall(r"[^a]{2,3}[A-Z]", "\n   S"), ['   S'])

        self.assertEqual(regex.findall(r"X(Y[^Y]+?){1,2}( |Q)+DEF",
          "XYABCYPPQ\nQ DEF"), [('YPPQ\n', ' ')])

        self.assertEqual(regex.findall(r"(\nTest(\n+.+?){0,2}?)?\n+End",
          "\nTest\nxyz\nxyz\nEnd"), [('\nTest\nxyz\nxyz', '\nxyz')])

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

    def test_re_match(self):
        self.assertEqual(regex.match('a', 'a')[:], ('a',))
        self.assertEqual(regex.match('(a)', 'a')[:], ('a', 'a'))
        self.assertEqual(regex.match(r'(a)', 'a')[0], 'a')
        self.assertEqual(regex.match(r'(a)', 'a')[1], 'a')
        self.assertEqual(regex.match(r'(a)', 'a').group(1, 1), ('a', 'a'))

        pat = regex.compile('((a)|(b))(c)?')
        self.assertEqual(pat.match('a')[:], ('a', 'a', 'a', None, None))
        self.assertEqual(pat.match('b')[:], ('b', 'b', None, 'b', None))
        self.assertEqual(pat.match('ac')[:], ('ac', 'a', 'a', None, 'c'))
        self.assertEqual(pat.match('bc')[:], ('bc', 'b', None, 'b', 'c'))
        self.assertEqual(pat.match('bc')[:], ('bc', 'b', None, 'b', 'c'))

        # A single group.
        m = regex.match('(a)', 'a')
        self.assertEqual(m.group(), 'a')
        self.assertEqual(m.group(0), 'a')
        self.assertEqual(m.group(1), 'a')
        self.assertEqual(m.group(1, 1), ('a', 'a'))

        pat = regex.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'))

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

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

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

        self.assertEqual(regex.findall(r"(?i)(.{1,40}?),(.{1,40}?)(?:;)+(.{1,80}).{1,40}?\3(\ |;)+(.{1,80}?)\1",
          "TEST, BEST; LEST ; Lest 123 Test, Best"), [('TEST', ' BEST',
          ' LEST', ' ', '123 ')])

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

    def test_expand(self):
        self.assertEqual(regex.match("(?P<first>first) (?P<second>second)",
          "first second").expand(r"\2 \1 \g<second> \g<first>"),
          'second first second first')

    def test_repeat_minmax(self):
        self.assertEqual(regex.match(r"^(\w){1}$", "abc"), None)
        self.assertEqual(regex.match(r"^(\w){1}?$", "abc"), None)
        self.assertEqual(regex.match(r"^(\w){1,2}$", "abc"), None)
        self.assertEqual(regex.match(r"^(\w){1,2}?$", "abc"), None)

        self.assertEqual(regex.match(r"^(\w){3}$", "abc")[1], 'c')
        self.assertEqual(regex.match(r"^(\w){1,3}$", "abc")[1], 'c')
        self.assertEqual(regex.match(r"^(\w){1,4}$", "abc")[1], 'c')
        self.assertEqual(regex.match(r"^(\w){3,4}?$", "abc")[1], 'c')
        self.assertEqual(regex.match(r"^(\w){3}?$", "abc")[1], 'c')
        self.assertEqual(regex.match(r"^(\w){1,3}?$", "abc")[1], 'c')
        self.assertEqual(regex.match(r"^(\w){1,4}?$", "abc")[1], 'c')
        self.assertEqual(regex.match(r"^(\w){3,4}?$", "abc")[1], 'c')

        self.assertEqual(regex.match("^x{1}$", "xxx"), None)
        self.assertEqual(regex.match("^x{1}?$", "xxx"), None)
        self.assertEqual(regex.match("^x{1,2}$", "xxx"), None)
        self.assertEqual(regex.match("^x{1,2}?$", "xxx"), None)

        self.assertEqual(regex.match("^x{1}", "xxx")[0], 'x')
        self.assertEqual(regex.match("^x{1}?", "xxx")[0], 'x')
        self.assertEqual(regex.match("^x{0,1}", "xxx")[0], 'x')
        self.assertEqual(regex.match("^x{0,1}?", "xxx")[0], '')

        self.assertEqual(bool(regex.match("^x{3}$", "xxx")), True)
        self.assertEqual(bool(regex.match("^x{1,3}$", "xxx")), True)
        self.assertEqual(bool(regex.match("^x{1,4}$", "xxx")), True)
        self.assertEqual(bool(regex.match("^x{3,4}?$", "xxx")), True)
        self.assertEqual(bool(regex.match("^x{3}?$", "xxx")), True)
        self.assertEqual(bool(regex.match("^x{1,3}?$", "xxx")), True)
        self.assertEqual(bool(regex.match("^x{1,4}?$", "xxx")), True)
        self.assertEqual(bool(regex.match("^x{3,4}?$", "xxx")), True)

        self.assertEqual(regex.match("^x{}$", "xxx"), None)
        self.assertEqual(bool(regex.match("^x{}$", "x{}")), True)

    def test_getattr(self):
        self.assertEqual(regex.compile("(?i)(a)(b)").pattern, '(?i)(a)(b)')
        self.assertEqual(regex.compile("(?i)(a)(b)").flags, regex.I | regex.U |
          regex.DEFAULT_VERSION)
        self.assertEqual(regex.compile(b"(?i)(a)(b)").flags, regex.A | regex.I
          | regex.DEFAULT_VERSION)
        self.assertEqual(regex.compile("(?i)(a)(b)").groups, 2)
        self.assertEqual(regex.compile("(?i)(a)(b)").groupindex, {})

        self.assertEqual(regex.compile("(?i)(?P<first>a)(?P<other>b)").groupindex,
          {'first': 1, 'other': 2})

        self.assertEqual(regex.match("(a)", "a").pos, 0)
        self.assertEqual(regex.match("(a)", "a").endpos, 1)

        self.assertEqual(regex.search("b(c)", "abcdef").pos, 0)
        self.assertEqual(regex.search("b(c)", "abcdef").endpos, 6)
        self.assertEqual(regex.search("b(c)", "abcdef").span(), (1, 3))
        self.assertEqual(regex.search("b(c)", "abcdef").span(1), (2, 3))

        self.assertEqual(regex.match("(a)", "a").string, 'a')
        self.assertEqual(regex.match("(a)", "a").regs, ((0, 1), (0, 1)))
        self.assertEqual(repr(type(regex.match("(a)", "a").re)),
          self.PATTERN_CLASS)

        # Issue 14260.
        p = regex.compile(r'abc(?P<n>def)')
        p.groupindex["n"] = 0
        self.assertEqual(p.groupindex["n"], 1)

    def test_special_escapes(self):
        self.assertEqual(regex.search(r"\b(b.)\b", "abcd abc bcd bx")[1], 'bx')
        self.assertEqual(regex.search(r"\B(b.)\B", "abc bcd bc abxd")[1], 'bx')
        self.assertEqual(regex.search(br"\b(b.)\b", b"abcd abc bcd bx",
          regex.LOCALE)[1], b'bx')
        self.assertEqual(regex.search(br"\B(b.)\B", b"abc bcd bc abxd",
          regex.LOCALE)[1], b'bx')
        self.assertEqual(regex.search(r"\b(b.)\b", "abcd abc bcd bx",
          regex.UNICODE)[1], 'bx')
        self.assertEqual(regex.search(r"\B(b.)\B", "abc bcd bc abxd",
          regex.UNICODE)[1], 'bx')

        self.assertEqual(regex.search(r"^abc$", "\nabc\n", regex.M)[0], 'abc')
        self.assertEqual(regex.search(r"^\Aabc\Z$", "abc", regex.M)[0], 'abc')
        self.assertEqual(regex.search(r"^\Aabc\Z$", "\nabc\n", regex.M), None)

        self.assertEqual(regex.search(br"\b(b.)\b", b"abcd abc bcd bx")[1],
          b'bx')
        self.assertEqual(regex.search(br"\B(b.)\B", b"abc bcd bc abxd")[1],
          b'bx')
        self.assertEqual(regex.search(br"^abc$", b"\nabc\n", regex.M)[0],
          b'abc')
        self.assertEqual(regex.search(br"^\Aabc\Z$", b"abc", regex.M)[0],
          b'abc')
        self.assertEqual(regex.search(br"^\Aabc\Z$", b"\nabc\n", regex.M),
          None)

        self.assertEqual(regex.search(r"\d\D\w\W\s\S", "1aa! a")[0], '1aa! a')
        self.assertEqual(regex.search(br"\d\D\w\W\s\S", b"1aa! a",
          regex.LOCALE)[0], b'1aa! a')
        self.assertEqual(regex.search(r"\d\D\w\W\s\S", "1aa! a",
          regex.UNICODE)[0], '1aa! a')

    def test_bigcharset(self):
        self.assertEqual(regex.match(r"([\u2222\u2223])", "\u2222")[1],
          '\u2222')
        self.assertEqual(regex.match(r"([\u2222\u2223])", "\u2222",
          regex.UNICODE)[1], '\u2222')
        self.assertEqual("".join(regex.findall(".",
          "e\xe8\xe9\xea\xeb\u0113\u011b\u0117", flags=regex.UNICODE)),
          'e\xe8\xe9\xea\xeb\u0113\u011b\u0117')
        self.assertEqual("".join(regex.findall(r"[e\xe8\xe9\xea\xeb\u0113\u011b\u0117]",
          "e\xe8\xe9\xea\xeb\u0113\u011b\u0117", flags=regex.UNICODE)),
          'e\xe8\xe9\xea\xeb\u0113\u011b\u0117')
        self.assertEqual("".join(regex.findall(r"e|\xe8|\xe9|\xea|\xeb|\u0113|\u011b|\u0117",
          "e\xe8\xe9\xea\xeb\u0113\u011b\u0117", flags=regex.UNICODE)),
          'e\xe8\xe9\xea\xeb\u0113\u011b\u0117')

    def test_anyall(self):
        self.assertEqual(regex.match("a.b", "a\nb", regex.DOTALL)[0], "a\nb")
        self.assertEqual(regex.match("a.*b", "a\n\nb", regex.DOTALL)[0],
          "a\n\nb")

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

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

    def test_ignore_case(self):
        self.assertEqual(regex.match("abc", "ABC", regex.I)[0], 'ABC')
        self.assertEqual(regex.match(b"abc", b"ABC", regex.I)[0], b'ABC')

        self.assertEqual(regex.match(r"(a\s[^a]*)", "a bb", regex.I)[1],
          'a bb')
        self.assertEqual(regex.match(r"(a\s[abc])", "a b", regex.I)[1], 'a b')
        self.assertEqual(regex.match(r"(a\s[abc]*)", "a bb", regex.I)[1],
          'a bb')
        self.assertEqual(regex.match(r"((a)\s\2)", "a a", regex.I)[1], 'a a')
        self.assertEqual(regex.match(r"((a)\s\2*)", "a aa", regex.I)[1],
          'a aa')
        self.assertEqual(regex.match(r"((a)\s(abc|a))", "a a", regex.I)[1],
          'a a')
        self.assertEqual(regex.match(r"((a)\s(abc|a)*)", "a aa", regex.I)[1],
          'a aa')

        # Issue 3511.
        self.assertEqual(regex.match(r"[Z-a]", "_").span(), (0, 1))
        self.assertEqual(regex.match(r"(?i)[Z-a]", "_").span(), (0, 1))

        self.assertEqual(bool(regex.match(r"(?i)nao", "nAo")), True)
        self.assertEqual(bool(regex.match(r"(?i)n\xE3o", "n\xC3o")), True)
        self.assertEqual(bool(regex.match(r"(?i)n\xE3o", "N\xC3O")), True)
        self.assertEqual(bool(regex.match(r"(?i)s", "\u017F")), True)

    def test_case_folding(self):
        self.assertEqual(regex.search(r"(?fi)ss", "SS").span(), (0, 2))
        self.assertEqual(regex.search(r"(?fi)SS", "ss").span(), (0, 2))
        self.assertEqual(regex.search(r"(?fi)SS",
          "\N{LATIN SMALL LETTER SHARP S}").span(), (0, 1))
        self.assertEqual(regex.search(r"(?fi)\N{LATIN SMALL LETTER SHARP S}",
          "SS").span(), (0, 2))

        self.assertEqual(regex.search(r"(?fi)\N{LATIN SMALL LIGATURE ST}",
          "ST").span(), (0, 2))
        self.assertEqual(regex.search(r"(?fi)ST",
          "\N{LATIN SMALL LIGATURE ST}").span(), (0, 1))
        self.assertEqual(regex.search(r"(?fi)ST",
          "\N{LATIN SMALL LIGATURE LONG S T}").span(), (0, 1))

        self.assertEqual(regex.search(r"(?fi)SST",
          "\N{LATIN SMALL LETTER SHARP S}t").span(), (0, 2))
        self.assertEqual(regex.search(r"(?fi)SST",
          "s\N{LATIN SMALL LIGATURE LONG S T}").span(), (0, 2))
        self.assertEqual(regex.search(r"(?fi)SST",
          "s\N{LATIN SMALL LIGATURE ST}").span(), (0, 2))
        self.assertEqual(regex.search(r"(?fi)\N{LATIN SMALL LIGATURE ST}",
          "SST").span(), (1, 3))
        self.assertEqual(regex.search(r"(?fi)SST",
          "s\N{LATIN SMALL LIGATURE ST}").span(), (0, 2))

        self.assertEqual(regex.search(r"(?fi)FFI",
          "\N{LATIN SMALL LIGATURE FFI}").span(), (0, 1))
        self.assertEqual(regex.search(r"(?fi)FFI",
          "\N{LATIN SMALL LIGATURE FF}i").span(), (0, 2))
        self.assertEqual(regex.search(r"(?fi)FFI",
          "f\N{LATIN SMALL LIGATURE FI}").span(), (0, 2))
        self.assertEqual(regex.search(r"(?fi)\N{LATIN SMALL LIGATURE FFI}",
          "FFI").span(), (0, 3))
        self.assertEqual(regex.search(r"(?fi)\N{LATIN SMALL LIGATURE FF}i",
          "FFI").span(), (0, 3))
        self.assertEqual(regex.search(r"(?fi)f\N{LATIN SMALL LIGATURE FI}",
          "FFI").span(), (0, 3))

        sigma = "\u03A3\u03C3\u03C2"
        for ch1 in sigma:
            for ch2 in sigma:
                if not regex.match(r"(?fi)" + ch1, ch2):
                    self.fail()

        self.assertEqual(bool(regex.search(r"(?iV1)ff", "\uFB00\uFB01")),
          True)
        self.assertEqual(bool(regex.search(r"(?iV1)ff", "\uFB01\uFB00")),
          True)
        self.assertEqual(bool(regex.search(r"(?iV1)fi", "\uFB00\uFB01")),
          True)
        self.assertEqual(bool(regex.search(r"(?iV1)fi", "\uFB01\uFB00")),
          True)
        self.assertEqual(bool(regex.search(r"(?iV1)fffi", "\uFB00\uFB01")),
          True)
        self.assertEqual(bool(regex.search(r"(?iV1)f\uFB03",
          "\uFB00\uFB01")), True)
        self.assertEqual(bool(regex.search(r"(?iV1)ff", "\uFB00\uFB01")),
          True)
        self.assertEqual(bool(regex.search(r"(?iV1)fi", "\uFB00\uFB01")),
          True)
        self.assertEqual(bool(regex.search(r"(?iV1)fffi", "\uFB00\uFB01")),
          True)
        self.assertEqual(bool(regex.search(r"(?iV1)f\uFB03",
          "\uFB00\uFB01")), True)
        self.assertEqual(bool(regex.search(r"(?iV1)f\uFB01", "\uFB00i")),
          True)
        self.assertEqual(bool(regex.search(r"(?iV1)f\uFB01", "\uFB00i")),
          True)

        self.assertEqual(regex.findall(r"(?iV0)\m(?:word){e<=3}\M(?<!\m(?:word){e<=1}\M)",
          "word word2 word word3 word word234 word23 word"), ["word234",
          "word23"])
        self.assertEqual(regex.findall(r"(?iV1)\m(?:word){e<=3}\M(?<!\m(?:word){e<=1}\M)",
          "word word2 word word3 word word234 word23 word"), ["word234",
          "word23"])

        self.assertEqual(regex.search(r"(?fi)a\N{LATIN SMALL LIGATURE FFI}ne",
          "  affine  ").span(), (2, 8))
        self.assertEqual(regex.search(r"(?fi)a(?:\N{LATIN SMALL LIGATURE FFI}|x)ne",
           "  affine  ").span(), (2, 8))
        self.assertEqual(regex.search(r"(?fi)a(?:\N{LATIN SMALL LIGATURE FFI}|xy)ne",
           "  affine  ").span(), (2, 8))
        self.assertEqual(regex.search(r"(?fi)a\L<options>ne", "affine",
          options=["\N{LATIN SMALL LIGATURE FFI}"]).span(), (0, 6))
        self.assertEqual(regex.search(r"(?fi)a\L<options>ne",
          "a\N{LATIN SMALL LIGATURE FFI}ne", options=["ffi"]).span(), (0, 4))

    def test_category(self):
        self.assertEqual(regex.match(r"(\s)", " ")[1], ' ')

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

    def test_search_coverage(self):
        self.assertEqual(regex.search(r"\s(b)", " b")[1], 'b')
        self.assertEqual(regex.search(r"a\s", "a ")[0], 'a ')

    def test_re_escape(self):
        p = ""
        self.assertEqual(regex.escape(p), p)
        for i in range(0, 256):
            p += chr(i)
            self.assertEqual(bool(regex.match(regex.escape(chr(i)), chr(i))),
              True)
            self.assertEqual(regex.match(regex.escape(chr(i)), chr(i)).span(),
              (0, 1))

        pat = regex.compile(regex.escape(p))
        self.assertEqual(pat.match(p).span(), (0, 256))

    def test_re_escape_byte(self):
        p = b""
        self.assertEqual(regex.escape(p), p)
        for i in range(0, 256):
            b = bytes([i])
            p += b
            self.assertEqual(bool(regex.match(regex.escape(b), b)), True)
            self.assertEqual(regex.match(regex.escape(b), b).span(), (0, 1))

        pat = regex.compile(regex.escape(p))
        self.assertEqual(pat.match(p).span(), (0, 256))

    def test_constants(self):
        if regex.I != regex.IGNORECASE:
            self.fail()
        if regex.L != regex.LOCALE:
            self.fail()
        if regex.M != regex.MULTILINE:
            self.fail()
        if regex.S != regex.DOTALL:
            self.fail()
        if regex.X != regex.VERBOSE:
            self.fail()

    def test_flags(self):
        for flag in [regex.I, regex.M, regex.X, regex.S, regex.L]:
            self.assertEqual(repr(type(regex.compile('^pattern$', flag))),
              self.PATTERN_CLASS)

    def test_sre_character_literals(self):
        for i in [0, 8, 16, 32, 64, 127, 128, 255]:
            self.assertEqual(bool(regex.match(r"\%03o" % i, chr(i))), True)
            self.assertEqual(bool(regex.match(r"\%03o0" % i, chr(i) + "0")),
              True)
            self.assertEqual(bool(regex.match(r"\%03o8" % i, chr(i) + "8")),
              True)
            self.assertEqual(bool(regex.match(r"\x%02x" % i, chr(i))), True)
            self.assertEqual(bool(regex.match(r"\x%02x0" % i, chr(i) + "0")),
              True)
            self.assertEqual(bool(regex.match(r"\x%02xz" % i, chr(i) + "z")),
              True)

        self.assertRaisesRegex(regex.error, self.INVALID_GROUP_REF, lambda:
          regex.match(r"\911", ""))

    def test_sre_character_class_literals(self):
        for i in [0, 8, 16, 32, 64, 127, 128, 255]:
            self.assertEqual(bool(regex.match(r"[\%03o]" % i, chr(i))), True)
            self.assertEqual(bool(regex.match(r"[\%03o0]" % i, chr(i))), True)
            self.assertEqual(bool(regex.match(r"[\%03o8]" % i, chr(i))), True)
            self.assertEqual(bool(regex.match(r"[\x%02x]" % i, chr(i))), True)
            self.assertEqual(bool(regex.match(r"[\x%02x0]" % i, chr(i))), True)
            self.assertEqual(bool(regex.match(r"[\x%02xz]" % i, chr(i))), True)

        self.assertRaisesRegex(regex.error, self.BAD_OCTAL_ESCAPE, lambda:
          regex.match(r"[\911]", ""))

    def test_bug_113254(self):
        self.assertEqual(regex.match(r'(a)|(b)', 'b').start(1), -1)
        self.assertEqual(regex.match(r'(a)|(b)', 'b').end(1), -1)
        self.assertEqual(regex.match(r'(a)|(b)', 'b').span(1), (-1, -1))

    def test_bug_527371(self):
        # Bug described in patches 527371/672491.
        self.assertEqual(regex.match(r'(a)?a','a').lastindex, None)
        self.assertEqual(regex.match(r'(a)(b)?b','ab').lastindex, 1)
        self.assertEqual(regex.match(r'(?P<a>a)(?P<b>b)?b','ab').lastgroup,
          'a')
        self.assertEqual(regex.match("(?P<a>a(b))", "ab").lastgroup, 'a')
        self.assertEqual(regex.match("((a))", "a").lastindex, 1)

    def test_bug_545855(self):
        # Bug 545855 -- This pattern failed to cause a compile error as it
        # should, instead provoking a TypeError.
        self.assertRaisesRegex(regex.error, self.BAD_SET, lambda:
          regex.compile('foo[a-'))

    def test_bug_418626(self):
        # Bugs 418626 at al. -- Testing Greg Chapman's addition of op code
        # SRE_OP_MIN_REPEAT_ONE for eliminating recursion on simple uses of
        # pattern '*?' on a long string.
        self.assertEqual(regex.match('.*?c', 10000 * 'ab' + 'cd').end(0),
          20001)
        self.assertEqual(regex.match('.*?cd', 5000 * 'ab' + 'c' + 5000 * 'ab' +
          'cde').end(0), 20003)
        self.assertEqual(regex.match('.*?cd', 20000 * 'abc' + 'de').end(0),
          60001)
        # Non-simple '*?' still used to hit the recursion limit, before the
        # non-recursive scheme was implemented.
        self.assertEqual(regex.search('(a|b)*?c', 10000 * 'ab' + 'cd').end(0),
          20001)

    def test_bug_612074(self):
        pat = "[" + regex.escape("\u2039") + "]"
        self.assertEqual(regex.compile(pat) and 1, 1)

    def test_stack_overflow(self):
        # Nasty cases that used to overflow the straightforward recursive
        # implementation of repeated groups.
        self.assertEqual(regex.match('(x)*', 50000 * 'x')[1], 'x')
        self.assertEqual(regex.match('(x)*y', 50000 * 'x' + 'y')[1], 'x')
        self.assertEqual(regex.match('(x)*?y', 50000 * 'x' + 'y')[1], 'x')

    def test_scanner(self):
        def s_ident(scanner, token): return token
        def s_operator(scanner, token): return "op%s" % token
        def s_float(scanner, token): return float(token)
        def s_int(scanner, token): return int(token)

        scanner = regex.Scanner([(r"[a-zA-Z_]\w*", s_ident), (r"\d+\.\d*",
          s_float), (r"\d+", s_int), (r"=|\+|-|\*|/", s_operator), (r"\s+",
            None), ])

        self.assertEqual(repr(type(scanner.scanner.scanner("").pattern)),
          self.PATTERN_CLASS)

        self.assertEqual(scanner.scan("sum = 3*foo + 312.50 + bar"), (['sum',
          'op=', 3, 'op*', 'foo', 'op+', 312.5, 'op+', 'bar'], ''))

    def test_bug_448951(self):
        # Bug 448951 (similar to 429357, but with single char match).
        # (Also test greedy matches.)
        for op in '', '?', '*':
            self.assertEqual(regex.match(r'((.%s):)?z' % op, 'z')[:], ('z',
              None, None))
            self.assertEqual(regex.match(r'((.%s):)?z' % op, 'a:z')[:], ('a:z',
              'a:', 'a'))

    def test_bug_725106(self):
        # Capturing groups in alternatives in repeats.
        self.assertEqual(regex.match('^((a)|b)*', 'abc')[:], ('ab', 'b', 'a'))
        self.assertEqual(regex.match('^(([ab])|c)*', 'abc')[:], ('abc', 'c',
          'b'))
        self.assertEqual(regex.match('^((d)|[ab])*', 'abc')[:], ('ab', 'b',
          None))
        self.assertEqual(regex.match('^((a)c|[ab])*', 'abc')[:], ('ab', 'b',
          None))
        self.assertEqual(regex.match('^((a)|b)*?c', 'abc')[:], ('abc', 'b',
          'a'))
        self.assertEqual(regex.match('^(([ab])|c)*?d', 'abcd')[:], ('abcd',
          'c', 'b'))
        self.assertEqual(regex.match('^((d)|[ab])*?c', 'abc')[:], ('abc', 'b',
          None))
        self.assertEqual(regex.match('^((a)c|[ab])*?c', 'abc')[:], ('abc', 'b',
          None))

    def test_bug_725149(self):
        # Mark_stack_base restoring before restoring marks.
        self.assertEqual(regex.match('(a)(?:(?=(b)*)c)*', 'abb')[:], ('a', 'a',
          None))
        self.assertEqual(regex.match('(a)((?!(b)*))*', 'abb')[:], ('a', 'a',
          None, None))

    def test_bug_764548(self):
        # Bug 764548, regex.compile() barfs on str/unicode subclasses.
        class my_unicode(str): pass
        pat = regex.compile(my_unicode("abc"))
        self.assertEqual(pat.match("xyz"), None)

    def test_finditer(self):
        it = regex.finditer(r":+", "a:b::c:::d")
        self.assertEqual([item[0] for item in it], [':', '::', ':::'])

    def test_bug_926075(self):
        if regex.compile('bug_926075') is regex.compile(b'bug_926075'):
            self.fail()

    def test_bug_931848(self):
        pattern = "[\u002E\u3002\uFF0E\uFF61]"
        self.assertEqual(regex.compile(pattern).split("a.b.c"), ['a', 'b',
          'c'])

    def test_bug_581080(self):
        it = regex.finditer(r"\s", "a b")
        self.assertEqual(next(it).span(), (1, 2))
        self.assertRaises(StopIteration, lambda: next(it))

        scanner = regex.compile(r"\s").scanner("a b")
        self.assertEqual(scanner.search().span(), (1, 2))
        self.assertEqual(scanner.search(), None)

    def test_bug_817234(self):
        it = regex.finditer(r".*", "asdf")
        self.assertEqual(next(it).span(), (0, 4))
        self.assertEqual(next(it).span(), (4, 4))
        self.assertRaises(StopIteration, lambda: next(it))

    def test_empty_array(self):
        # SF buf 1647541.
        import array
        for typecode in 'bBuhHiIlLfd':
            a = array.array(typecode)
            self.assertEqual(regex.compile(b"bla").match(a), None)
            self.assertEqual(regex.compile(b"").match(a)[1 : ], ())

    def test_inline_flags(self):
        # Bug #1700.
        upper_char = chr(0x1ea0) # Latin Capital Letter A with Dot Below
        lower_char = chr(0x1ea1) # Latin Small Letter A with Dot Below

        p = regex.compile(upper_char, regex.I | regex.U)
        self.assertEqual(bool(p.match(lower_char)), True)

        p = regex.compile(lower_char, regex.I | regex.U)
        self.assertEqual(bool(p.match(upper_char)), True)

        p = regex.compile('(?i)' + upper_char, regex.U)
        self.assertEqual(bool(p.match(lower_char)), True)

        p = regex.compile('(?i)' + lower_char, regex.U)
        self.assertEqual(bool(p.match(upper_char)), True)

        p = regex.compile('(?iu)' + upper_char)
        self.assertEqual(bool(p.match(lower_char)), True)

        p = regex.compile('(?iu)' + lower_char)
        self.assertEqual(bool(p.match(upper_char)), True)

        # Changed to positional flags in regex 2023.12.23.
        self.assertEqual(bool(regex.match(r"(?i)a", "A")), True)
        self.assertEqual(regex.match(r"a(?i)", "A"), None)

    def test_dollar_matches_twice(self):
        # $ matches the end of string, and just before the terminating \n.
        pattern = regex.compile('$')
        self.assertEqual(pattern.sub('#', 'a\nb\n'), 'a\nb#\n#')
        self.assertEqual(pattern.sub('#', 'a\nb\nc'), 'a\nb\nc#')
        self.assertEqual(pattern.sub('#', '\n'), '#\n#')

        pattern = regex.compile('$', regex.MULTILINE)
        self.assertEqual(pattern.sub('#', 'a\nb\n' ), 'a#\nb#\n#')
        self.assertEqual(pattern.sub('#', 'a\nb\nc'), 'a#\nb#\nc#')
        self.assertEqual(pattern.sub('#', '\n'), '#\n#')

    def test_bytes_str_mixing(self):
        # Mixing str and bytes is disallowed.
        pat = regex.compile('.')
        bpat = regex.compile(b'.')
        self.assertRaisesRegex(TypeError, self.STR_PAT_ON_BYTES, lambda:
          pat.match(b'b'))
        self.assertRaisesRegex(TypeError, self.BYTES_PAT_ON_STR, lambda:
          bpat.match('b'))
        self.assertRaisesRegex(TypeError, self.STR_PAT_BYTES_TEMPL, lambda:
          pat.sub(b'b', 'c'))
        self.assertRaisesRegex(TypeError, self.STR_PAT_ON_BYTES, lambda:
          pat.sub('b', b'c'))
        self.assertRaisesRegex(TypeError, self.STR_PAT_ON_BYTES, lambda:
          pat.sub(b'b', b'c'))
        self.assertRaisesRegex(TypeError, self.BYTES_PAT_ON_STR, lambda:
          bpat.sub(b'b', 'c'))
        self.assertRaisesRegex(TypeError, self.BYTES_PAT_STR_TEMPL, lambda:
          bpat.sub('b', b'c'))
        self.assertRaisesRegex(TypeError, self.BYTES_PAT_ON_STR, lambda:
          bpat.sub('b', 'c'))

        self.assertRaisesRegex(ValueError, self.BYTES_PAT_UNI_FLAG, lambda:
          regex.compile(br'\w', regex.UNICODE))
        self.assertRaisesRegex(ValueError, self.BYTES_PAT_UNI_FLAG, lambda:
          regex.compile(br'(?u)\w'))
        self.assertRaisesRegex(ValueError, self.MIXED_FLAGS, lambda:
          regex.compile(r'\w', regex.UNICODE | regex.ASCII))
        self.assertRaisesRegex(ValueError, self.MIXED_FLAGS, lambda:
          regex.compile(r'(?u)\w', regex.ASCII))
        self.assertRaisesRegex(ValueError, self.MIXED_FLAGS, lambda:
          regex.compile(r'(?a)\w', regex.UNICODE))
        self.assertRaisesRegex(ValueError, self.MIXED_FLAGS, lambda:
          regex.compile(r'(?au)\w'))

    def test_ascii_and_unicode_flag(self):
        # String patterns.
        for flags in (0, regex.UNICODE):
            pat = regex.compile('\xc0', flags | regex.IGNORECASE)
            self.assertEqual(bool(pat.match('\xe0')), True)
            pat = regex.compile(r'\w', flags)
            self.assertEqual(bool(pat.match('\xe0')), True)

        pat = regex.compile('\xc0', regex.ASCII | regex.IGNORECASE)
        self.assertEqual(pat.match('\xe0'), None)
        pat = regex.compile('(?a)\xc0', regex.IGNORECASE)
        self.assertEqual(pat.match('\xe0'), None)
        pat = regex.compile(r'\w', regex.ASCII)
        self.assertEqual(pat.match('\xe0'), None)
        pat = regex.compile(r'(?a)\w')
        self.assertEqual(pat.match('\xe0'), None)

        # Bytes patterns.
        for flags in (0, regex.ASCII):
            pat = regex.compile(b'\xc0', flags | regex.IGNORECASE)
            self.assertEqual(pat.match(b'\xe0'), None)
            pat = regex.compile(br'\w')
            self.assertEqual(pat.match(b'\xe0'), None)

        self.assertRaisesRegex(ValueError, self.MIXED_FLAGS, lambda:
          regex.compile(r'(?au)\w'))

    def test_subscripting_match(self):
        m = regex.match(r'(?<a>\w)', 'xy')
        if not m:
            self.fail("Failed: expected match but returned None")
        elif not m or m[0] != m.group(0) or m[1] != m.group(1):
            self.fail("Failed")
        if not m:
            self.fail("Failed: expected match but returned None")
        elif m[:] != ('x', 'x'):
            self.fail("Failed: expected \"('x', 'x')\" but got {} instead".format(ascii(m[:])))

    def test_new_named_groups(self):
        m0 = regex.match(r'(?P<a>\w)', 'x')
        m1 = regex.match(r'(?<a>\w)', 'x')
        if not (m0 and m1 and m0[:] == m1[:]):
            self.fail("Failed")

    def test_properties(self):
        self.assertEqual(regex.match(b'(?ai)\xC0', b'\xE0'), None)
        self.assertEqual(regex.match(br'(?ai)\xC0', b'\xE0'), None)
        self.assertEqual(regex.match(br'(?a)\w', b'\xE0'), None)
        self.assertEqual(bool(regex.match(r'\w', '\xE0')), True)

        # Dropped the following test. It's not possible to determine what the
        # correct result should be in the general case.
#        self.assertEqual(bool(regex.match(br'(?L)\w', b'\xE0')),
#          b'\xE0'.isalnum())

        self.assertEqual(bool(regex.match(br'(?L)\d', b'0')), True)
        self.assertEqual(bool(regex.match(br'(?L)\s', b' ')), True)
        self.assertEqual(bool(regex.match(br'(?L)\w', b'a')), True)
        self.assertEqual(regex.match(br'(?L)\d', b'?'), None)
        self.assertEqual(regex.match(br'(?L)\s', b'?'), None)
        self.assertEqual(regex.match(br'(?L)\w', b'?'), None)

        self.assertEqual(regex.match(br'(?L)\D', b'0'), None)
        self.assertEqual(regex.match(br'(?L)\S', b' '), None)
        self.assertEqual(regex.match(br'(?L)\W', b'a'), None)
        self.assertEqual(bool(regex.match(br'(?L)\D', b'?')), True)
        self.assertEqual(bool(regex.match(br'(?L)\S', b'?')), True)
        self.assertEqual(bool(regex.match(br'(?L)\W', b'?')), True)

        self.assertEqual(bool(regex.match(r'\p{Cyrillic}',
          '\N{CYRILLIC CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'(?i)\p{Cyrillic}',
          '\N{CYRILLIC CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'\p{IsCyrillic}',
          '\N{CYRILLIC CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'\p{Script=Cyrillic}',
          '\N{CYRILLIC CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'\p{InCyrillic}',
          '\N{CYRILLIC CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'\p{Block=Cyrillic}',
          '\N{CYRILLIC CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'[[:Cyrillic:]]',
          '\N{CYRILLIC CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'[[:IsCyrillic:]]',
          '\N{CYRILLIC CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'[[:Script=Cyrillic:]]',
          '\N{CYRILLIC CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'[[:InCyrillic:]]',
          '\N{CYRILLIC CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'[[:Block=Cyrillic:]]',
          '\N{CYRILLIC CAPITAL LETTER A}')), True)

        self.assertEqual(bool(regex.match(r'\P{Cyrillic}',
          '\N{LATIN CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'\P{IsCyrillic}',
          '\N{LATIN CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'\P{Script=Cyrillic}',
          '\N{LATIN CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'\P{InCyrillic}',
          '\N{LATIN CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'\P{Block=Cyrillic}',
          '\N{LATIN CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'\p{^Cyrillic}',
          '\N{LATIN CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'\p{^IsCyrillic}',
          '\N{LATIN CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'\p{^Script=Cyrillic}',
          '\N{LATIN CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'\p{^InCyrillic}',
          '\N{LATIN CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'\p{^Block=Cyrillic}',
          '\N{LATIN CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'[[:^Cyrillic:]]',
          '\N{LATIN CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'[[:^IsCyrillic:]]',
          '\N{LATIN CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'[[:^Script=Cyrillic:]]',
          '\N{LATIN CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'[[:^InCyrillic:]]',
          '\N{LATIN CAPITAL LETTER A}')), True)
        self.assertEqual(bool(regex.match(r'[[:^Block=Cyrillic:]]',
          '\N{LATIN CAPITAL LETTER A}')), True)

        self.assertEqual(bool(regex.match(r'\d', '0')), True)
        self.assertEqual(bool(regex.match(r'\s', ' ')), True)
        self.assertEqual(bool(regex.match(r'\w', 'A')), True)
        self.assertEqual(regex.match(r"\d", "?"), None)
        self.assertEqual(regex.match(r"\s", "?"), None)
        self.assertEqual(regex.match(r"\w", "?"), None)
        self.assertEqual(regex.match(r"\D", "0"), None)
        self.assertEqual(regex.match(r"\S", " "), None)
        self.assertEqual(regex.match(r"\W", "A"), None)
        self.assertEqual(bool(regex.match(r'\D', '?')), True)
        self.assertEqual(bool(regex.match(r'\S', '?')), True)
        self.assertEqual(bool(regex.match(r'\W', '?')), True)

        self.assertEqual(bool(regex.match(r'\p{L}', 'A')), True)
        self.assertEqual(bool(regex.match(r'\p{L}', 'a')), True)
        self.assertEqual(bool(regex.match(r'\p{Lu}', 'A')), True)
        self.assertEqual(bool(regex.match(r'\p{Ll}', 'a')), True)

        self.assertEqual(bool(regex.match(r'(?i)a', 'a')), True)
        self.assertEqual(bool(regex.match(r'(?i)a', 'A')), True)

        self.assertEqual(bool(regex.match(r'\w', '0')), True)
        self.assertEqual(bool(regex.match(r'\w', 'a')), True)
        self.assertEqual(bool(regex.match(r'\w', '_')), True)

        self.assertEqual(regex.match(r"\X", "\xE0").span(), (0, 1))
        self.assertEqual(regex.match(r"\X", "a\u0300").span(), (0, 2))
        self.assertEqual(regex.findall(r"\X",
          "a\xE0a\u0300e\xE9e\u0301"), ['a', '\xe0', 'a\u0300', 'e',
          '\xe9', 'e\u0301'])
        self.assertEqual(regex.findall(r"\X{3}",
          "a\xE0a\u0300e\xE9e\u0301"), ['a\xe0a\u0300', 'e\xe9e\u0301'])
        self.assertEqual(regex.findall(r"\X", "\r\r\n\u0301A\u0301"),
          ['\r', '\r\n', '\u0301', 'A\u0301'])

        self.assertEqual(bool(regex.match(r'\p{Ll}', 'a')), True)

        chars_u = "-09AZaz_\u0393\u03b3"
        chars_b = b"-09AZaz_"
        word_set = set("Ll Lm Lo Lt Lu Mc Me Mn Nd Nl No Pc".split())

        tests = [
            (r"\w", chars_u, "09AZaz_\u0393\u03b3"),
            (r"[[:word:]]", chars_u, "09AZaz_\u0393\u03b3"),
            (r"\W", chars_u, "-"),
            (r"[[:^word:]]", chars_u, "-"),
            (r"\d", chars_u, "09"),
            (r"[[:digit:]]", chars_u, "09"),
            (r"\D", chars_u, "-AZaz_\u0393\u03b3"),
            (r"[[:^digit:]]", chars_u, "-AZaz_\u0393\u03b3"),
            (r"[[:alpha:]]", chars_u, "AZaz\u0393\u03b3"),
            (r"[[:^alpha:]]", chars_u, "-09_"),
            (r"[[:alnum:]]", chars_u, "09AZaz\u0393\u03b3"),
            (r"[[:^alnum:]]", chars_u, "-_"),
            (r"[[:xdigit:]]", chars_u, "09Aa"),
            (r"[[:^xdigit:]]", chars_u, "-Zz_\u0393\u03b3"),
            (r"\p{InBasicLatin}", "a\xE1", "a"),
            (r"\P{InBasicLatin}", "a\xE1", "\xE1"),
            (r"(?i)\p{InBasicLatin}", "a\xE1", "a"),
            (r"(?i)\P{InBasicLatin}", "a\xE1", "\xE1"),

            (br"(?L)\w", chars_b, b"09AZaz_"),
            (br"(?L)[[:word:]]", chars_b, b"09AZaz_"),
            (br"(?L)\W", chars_b, b"-"),
            (br"(?L)[[:^word:]]", chars_b, b"-"),
            (br"(?L)\d", chars_b, b"09"),
            (br"(?L)[[:digit:]]", chars_b, b"09"),
            (br"(?L)\D", chars_b, b"-AZaz_"),
            (br"(?L)[[:^digit:]]", chars_b, b"-AZaz_"),
            (br"(?L)[[:alpha:]]", chars_b, b"AZaz"),
            (br"(?L)[[:^alpha:]]", chars_b, b"-09_"),
            (br"(?L)[[:alnum:]]", chars_b, b"09AZaz"),
            (br"(?L)[[:^alnum:]]", chars_b, b"-_"),
            (br"(?L)[[:xdigit:]]", chars_b, b"09Aa"),
            (br"(?L)[[:^xdigit:]]", chars_b, b"-Zz_"),

            (br"(?a)\w", chars_b, b"09AZaz_"),
            (br"(?a)[[:word:]]", chars_b, b"09AZaz_"),
            (br"(?a)\W", chars_b, b"-"),
            (br"(?a)[[:^word:]]", chars_b, b"-"),
            (br"(?a)\d", chars_b, b"09"),
            (br"(?a)[[:digit:]]", chars_b, b"09"),
            (br"(?a)\D", chars_b, b"-AZaz_"),
            (br"(?a)[[:^digit:]]", chars_b, b"-AZaz_"),
            (br"(?a)[[:alpha:]]", chars_b, b"AZaz"),
            (br"(?a)[[:^alpha:]]", chars_b, b"-09_"),
            (br"(?a)[[:alnum:]]", chars_b, b"09AZaz"),
            (br"(?a)[[:^alnum:]]", chars_b, b"-_"),
            (br"(?a)[[:xdigit:]]", chars_b, b"09Aa"),
            (br"(?a)[[:^xdigit:]]", chars_b, b"-Zz_"),
        ]
        for pattern, chars, expected in tests:
            try:
                if chars[ : 0].join(regex.findall(pattern, chars)) != expected:
                    self.fail("Failed: {}".format(pattern))
            except Exception as e:
                self.fail("Failed: {} raised {}".format(pattern, ascii(e)))

        self.assertEqual(bool(regex.match(r"\p{NumericValue=0}", "0")),
          True)
        self.assertEqual(bool(regex.match(r"\p{NumericValue=1/2}",
          "\N{VULGAR FRACTION ONE HALF}")), True)
        self.assertEqual(bool(regex.match(r"\p{NumericValue=0.5}",
          "\N{VULGAR FRACTION ONE HALF}")), True)

    def test_word_class(self):
        self.assertEqual(regex.findall(r"\w+",
          " \u0939\u093f\u0928\u094d\u0926\u0940,"),
          ['\u0939\u093f\u0928\u094d\u0926\u0940'])
        self.assertEqual(regex.findall(r"\W+",
          " \u0939\u093f\u0928\u094d\u0926\u0940,"), [' ', ','])
        self.assertEqual(regex.split(r"(?V1)\b",
          " \u0939\u093f\u0928\u094d\u0926\u0940,"), [' ',
          '\u0939\u093f\u0928\u094d\u0926\u0940', ','])
        self.assertEqual(regex.split(r"(?V1)\B",
          " \u0939\u093f\u0928\u094d\u0926\u0940,"), ['', ' \u0939',
          '\u093f', '\u0928', '\u094d', '\u0926', '\u0940,', ''])

    def test_search_anchor(self):
        self.assertEqual(regex.findall(r"\G\w{2}", "abcd ef"), ['ab', 'cd'])

    def test_search_reverse(self):
        self.assertEqual(regex.findall(r"(?r).", "abc"), ['c', 'b', 'a'])
        self.assertEqual(regex.findall(r"(?r).", "abc", overlapped=True), ['c',
          'b', 'a'])
        self.assertEqual(regex.findall(r"(?r)..", "abcde"), ['de', 'bc'])
        self.assertEqual(regex.findall(r"(?r)..", "abcde", overlapped=True),
          ['de', 'cd', 'bc', 'ab'])
        self.assertEqual(regex.findall(r"(?r)(.)(-)(.)", "a-b-c",
          overlapped=True), [("b", "-", "c"), ("a", "-", "b")])

        self.assertEqual([m[0] for m in regex.finditer(r"(?r).", "abc")], ['c',
          'b', 'a'])
        self.assertEqual([m[0] for m in regex.finditer(r"(?r)..", "abcde",
          overlapped=True)], ['de', 'cd', 'bc', 'ab'])
        self.assertEqual([m[0] for m in regex.finditer(r"(?r).", "abc")], ['c',
          'b', 'a'])
        self.assertEqual([m[0] for m in regex.finditer(r"(?r)..", "abcde",
          overlapped=True)], ['de', 'cd', 'bc', 'ab'])

        self.assertEqual(regex.findall(r"^|\w+", "foo bar"), ['', 'foo',
          'bar'])
        self.assertEqual(regex.findall(r"(?V1)^|\w+", "foo bar"), ['', 'foo',
          'bar'])
        self.assertEqual(regex.findall(r"(?r)^|\w+", "foo bar"), ['bar', 'foo',
          ''])
        self.assertEqual(regex.findall(r"(?rV1)^|\w+", "foo bar"), ['bar',
          'foo', ''])

        self.assertEqual([m[0] for m in regex.finditer(r"^|\w+", "foo bar")],
          ['', 'foo', 'bar'])
        self.assertEqual([m[0] for m in regex.finditer(r"(?V1)^|\w+",
          "foo bar")], ['', 'foo', 'bar'])
        self.assertEqual([m[0] for m in regex.finditer(r"(?r)^|\w+",
          "foo bar")], ['bar', 'foo', ''])
        self.assertEqual([m[0] for m in regex.finditer(r"(?rV1)^|\w+",
          "foo bar")], ['bar', 'foo', ''])

        self.assertEqual(regex.findall(r"\G\w{2}", "abcd ef"), ['ab', 'cd'])
        self.assertEqual(regex.findall(r".{2}(?<=\G.*)", "abcd"), ['ab', 'cd'])
        self.assertEqual(regex.findall(r"(?r)\G\w{2}", "abcd ef"), [])
        self.assertEqual(regex.findall(r"(?r)\w{2}\G", "abcd ef"), ['ef'])

        self.assertEqual(regex.findall(r"q*", "qqwe"), ['qq', '', '', ''])
        self.assertEqual(regex.findall(r"(?V1)q*", "qqwe"), ['qq', '', '', ''])
        self.assertEqual(regex.findall(r"(?r)q*", "qqwe"), ['', '', 'qq', ''])
        self.assertEqual(regex.findall(r"(?rV1)q*", "qqwe"), ['', '', 'qq',
          ''])

        self.assertEqual(regex.findall(".", "abcd", pos=1, endpos=3), ['b',
          'c'])
        self.assertEqual(regex.findall(".", "abcd", pos=1, endpos=-1), ['b',
          'c'])
        self.assertEqual([m[0] for m in regex.finditer(".", "abcd", pos=1,
          endpos=3)], ['b', 'c'])
        self.assertEqual([m[0] for m in regex.finditer(".", "abcd", pos=1,
          endpos=-1)], ['b', 'c'])

        self.assertEqual([m[0] for m in regex.finditer("(?r).", "abcd", pos=1,
          endpos=3)], ['c', 'b'])
        self.assertEqual([m[0] for m in regex.finditer("(?r).", "abcd", pos=1,
          endpos=-1)], ['c', 'b'])
        self.assertEqual(regex.findall("(?r).", "abcd", pos=1, endpos=3), ['c',
          'b'])
        self.assertEqual(regex.findall("(?r).", "abcd", pos=1, endpos=-1),
          ['c', 'b'])

        self.assertEqual(regex.findall(r"[ab]", "aB", regex.I), ['a', 'B'])
        self.assertEqual(regex.findall(r"(?r)[ab]", "aB", regex.I), ['B', 'a'])

        self.assertEqual(regex.findall(r"(?r).{2}", "abc"), ['bc'])
        self.assertEqual(regex.findall(r"(?r).{2}", "abc", overlapped=True),
          ['bc', 'ab'])
        self.assertEqual(regex.findall(r"(\w+) (\w+)",
          "first second third fourth fifth"), [('first', 'second'), ('third',
          'fourth')])
        self.assertEqual(regex.findall(r"(?r)(\w+) (\w+)",
          "first second third fourth fifth"), [('fourth', 'fifth'), ('second',
          'third')])

        self.assertEqual([m[0] for m in regex.finditer(r"(?r).{2}", "abc")],
          ['bc'])
        self.assertEqual([m[0] for m in regex.finditer(r"(?r).{2}", "abc",
          overlapped=True)], ['bc', 'ab'])
        self.assertEqual([m[0] for m in regex.finditer(r"(\w+) (\w+)",
          "first second third fourth fifth")], ['first second',
          'third fourth'])
        self.assertEqual([m[0] for m in regex.finditer(r"(?r)(\w+) (\w+)",
          "first second third fourth fifth")], ['fourth fifth',
          'second third'])

        self.assertEqual(regex.search("abcdef", "abcdef").span(), (0, 6))
        self.assertEqual(regex.search("(?r)abcdef", "abcdef").span(), (0, 6))
        self.assertEqual(regex.search("(?i)abcdef", "ABCDEF").span(), (0, 6))
        self.assertEqual(regex.search("(?ir)abcdef", "ABCDEF").span(), (0, 6))

        self.assertEqual(regex.sub(r"(.)", r"\1", "abc"), 'abc')
        self.assertEqual(regex.sub(r"(?r)(.)", r"\1", "abc"), 'abc')

    def test_atomic(self):
        # Issue 433030.
        self.assertEqual(regex.search(r"(?>a*)a", "aa"), None)

    def test_possessive(self):
        # Single-character non-possessive.
        self.assertEqual(regex.search(r"a?a", "a").span(), (0, 1))
        self.assertEqual(regex.search(r"a*a", "aaa").span(), (0, 3))
        self.assertEqual(regex.search(r"a+a", "aaa").span(), (0, 3))
        self.assertEqual(regex.search(r"a{1,3}a", "aaa").span(), (0, 3))

        # Multiple-character non-possessive.
        self.assertEqual(regex.search(r"(?:ab)?ab", "ab").span(), (0, 2))
        self.assertEqual(regex.search(r"(?:ab)*ab", "ababab").span(), (0, 6))
        self.assertEqual(regex.search(r"(?:ab)+ab", "ababab").span(), (0, 6))
        self.assertEqual(regex.search(r"(?:ab){1,3}ab", "ababab").span(), (0,
          6))

        # Single-character possessive.
        self.assertEqual(regex.search(r"a?+a", "a"), None)
        self.assertEqual(regex.search(r"a*+a", "aaa"), None)
        self.assertEqual(regex.search(r"a++a", "aaa"), None)
        self.assertEqual(regex.search(r"a{1,3}+a", "aaa"), None)

        # Multiple-character possessive.
        self.assertEqual(regex.search(r"(?:ab)?+ab", "ab"), None)
        self.assertEqual(regex.search(r"(?:ab)*+ab", "ababab"), None)
        self.assertEqual(regex.search(r"(?:ab)++ab", "ababab"), None)
        self.assertEqual(regex.search(r"(?:ab){1,3}+ab", "ababab"), None)

    def test_zerowidth(self):
        # Issue 3262.
        if sys.version_info >= (3, 7, 0):
            self.assertEqual(regex.split(r"\b", "a b"), ['', 'a', ' ', 'b',
              ''])
        else:
            self.assertEqual(regex.split(r"\b", "a b"), ['a b'])
        self.assertEqual(regex.split(r"(?V1)\b", "a b"), ['', 'a', ' ', 'b',
          ''])

        # Issue 1647489.
        self.assertEqual(regex.findall(r"^|\w+", "foo bar"), ['', 'foo',
          'bar'])
        self.assertEqual([m[0] for m in regex.finditer(r"^|\w+", "foo bar")],
          ['', 'foo', 'bar'])
        self.assertEqual(regex.findall(r"(?r)^|\w+", "foo bar"), ['bar',
          'foo', ''])
        self.assertEqual([m[0] for m in regex.finditer(r"(?r)^|\w+",
          "foo bar")], ['bar', 'foo', ''])
        self.assertEqual(regex.findall(r"(?V1)^|\w+", "foo bar"), ['', 'foo',
          'bar'])
        self.assertEqual([m[0] for m in regex.finditer(r"(?V1)^|\w+",
          "foo bar")], ['', 'foo', 'bar'])
        self.assertEqual(regex.findall(r"(?rV1)^|\w+", "foo bar"), ['bar',
          'foo', ''])
        self.assertEqual([m[0] for m in regex.finditer(r"(?rV1)^|\w+",
          "foo bar")], ['bar', 'foo', ''])

        if sys.version_info >= (3, 7, 0):
            self.assertEqual(regex.split("", "xaxbxc"), ['', 'x', 'a', 'x',
              'b', 'x', 'c', ''])
            self.assertEqual([m for m in regex.splititer("", "xaxbxc")], ['',
              'x', 'a', 'x', 'b', 'x', 'c', ''])
        else:
            self.assertEqual(regex.split("", "xaxbxc"), ['xaxbxc'])
            self.assertEqual([m for m in regex.splititer("", "xaxbxc")],
              ['xaxbxc'])

        if sys.version_info >= (3, 7, 0):
            self.assertEqual(regex.split("(?r)", "xaxbxc"), ['', 'c', 'x', 'b',
              'x', 'a', 'x', ''])
            self.assertEqual([m for m in regex.splititer("(?r)", "xaxbxc")],
              ['', 'c', 'x', 'b', 'x', 'a', 'x', ''])
        else:
            self.assertEqual(regex.split("(?r)", "xaxbxc"), ['xaxbxc'])
            self.assertEqual([m for m in regex.splititer("(?r)", "xaxbxc")],
              ['xaxbxc'])

        self.assertEqual(regex.split("(?V1)", "xaxbxc"), ['', 'x', 'a', 'x',
          'b', 'x', 'c', ''])
        self.assertEqual([m for m in regex.splititer("(?V1)", "xaxbxc")], ['',
          'x', 'a', 'x', 'b', 'x', 'c', ''])

        self.assertEqual(regex.split("(?rV1)", "xaxbxc"), ['', 'c', 'x', 'b',
          'x', 'a', 'x', ''])
        self.assertEqual([m for m in regex.splititer("(?rV1)", "xaxbxc")], ['',
          'c', 'x', 'b', 'x', 'a', 'x', ''])

    def test_scoped_and_inline_flags(self):
        # Issues 433028, 433024, 433027.
        self.assertEqual(regex.search(r"(?i)Ab", "ab").span(), (0, 2))
        self.assertEqual(regex.search(r"(?i:A)b", "ab").span(), (0, 2))
        # Changed to positional flags in regex 2023.12.23.
        self.assertEqual(regex.search(r"A(?i)b", "ab"), None)

        self.assertEqual(regex.search(r"(?V0)Ab", "ab"), None)
        self.assertEqual(regex.search(r"(?V1)Ab", "ab"), None)
        self.assertEqual(regex.search(r"(?-i)Ab", "ab", flags=regex.I), None)
        self.assertEqual(regex.search(r"(?-i:A)b", "ab", flags=regex.I), None)
        self.assertEqual(regex.search(r"A(?-i)b", "ab", flags=regex.I).span(),
          (0, 2))

    def test_repeated_repeats(self):
        # Issue 2537.
        self.assertEqual(regex.search(r"(?:a+)+", "aaa").span(), (0, 3))
        self.assertEqual(regex.search(r"(?:(?:ab)+c)+", "abcabc").span(), (0,
          6))

        # Hg issue 286.
        self.assertEqual(regex.search(r"(?:a+){2,}", "aaa").span(), (0, 3))

    def test_lookbehind(self):
        self.assertEqual(regex.search(r"123(?<=a\d+)", "a123").span(), (1, 4))
        self.assertEqual(regex.search(r"123(?<=a\d+)", "b123"), None)
        self.assertEqual(regex.search(r"123(?<!a\d+)", "a123"), None)
        self.assertEqual(regex.search(r"123(?<!a\d+)", "b123").span(), (1, 4))

        self.assertEqual(bool(regex.match("(a)b(?<=b)(c)", "abc")), True)
        self.assertEqual(regex.match("(a)b(?<=c)(c)", "abc"), None)
        self.assertEqual(bool(regex.match("(a)b(?=c)(c)", "abc")), True)
        self.assertEqual(regex.match("(a)b(?=b)(c)", "abc"), None)

        self.assertEqual(regex.match("(?:(a)|(x))b(?<=(?(2)x|c))c", "abc"),
          None)
        self.assertEqual(regex.match("(?:(a)|(x))b(?<=(?(2)b|x))c", "abc"),
          None)
        self.assertEqual(bool(regex.match("(?:(a)|(x))b(?<=(?(2)x|b))c",
          "abc")), True)
        self.assertEqual(regex.match("(?:(a)|(x))b(?<=(?(1)c|x))c", "abc"),
          None)
        self.assertEqual(bool(regex.match("(?:(a)|(x))b(?<=(?(1)b|x))c",
          "abc")), True)

        self.assertEqual(bool(regex.match("(?:(a)|(x))b(?=(?(2)x|c))c",
          "abc")), True)
        self.assertEqual(regex.match("(?:(a)|(x))b(?=(?(2)c|x))c", "abc"),
          None)
        self.assertEqual(bool(regex.match("(?:(a)|(x))b(?=(?(2)x|c))c",
          "abc")), True)
        self.assertEqual(regex.match("(?:(a)|(x))b(?=(?(1)b|x))c", "abc"),
          None)
        self.assertEqual(bool(regex.match("(?:(a)|(x))b(?=(?(1)c|x))c",
          "abc")), True)

        self.assertEqual(regex.match("(a)b(?<=(?(2)x|c))(c)", "abc"), None)
        self.assertEqual(regex.match("(a)b(?<=(?(2)b|x))(c)", "abc"), None)
        self.assertEqual(regex.match("(a)b(?<=(?(1)c|x))(c)", "abc"), None)
        self.assertEqual(bool(regex.match("(a)b(?<=(?(1)b|x))(c)", "abc")),
          True)

        self.assertEqual(bool(regex.match("(a)b(?=(?(2)x|c))(c)", "abc")),
          True)
        self.assertEqual(regex.match("(a)b(?=(?(2)b|x))(c)", "abc"), None)
        self.assertEqual(bool(regex.match("(a)b(?=(?(1)c|x))(c)", "abc")),
          True)

        self.assertEqual(repr(type(regex.compile(r"(a)\2(b)"))),
          self.PATTERN_CLASS)

    def test_unmatched_in_sub(self):
        # Issue 1519638.

        if sys.version_info >= (3, 7, 0):
            self.assertEqual(regex.sub(r"(?V0)(x)?(y)?", r"\2-\1", "xy"),
              'y-x-')
        else:
            self.assertEqual(regex.sub(r"(?V0)(x)?(y)?", r"\2-\1", "xy"),
              'y-x')
        self.assertEqual(regex.sub(r"(?V1)(x)?(y)?", r"\2-\1", "xy"), 'y-x-')
        if sys.version_info >= (3, 7, 0):
            self.assertEqual(regex.sub(r"(?V0)(x)?(y)?", r"\2-\1", "x"), '-x-')
        else:
            self.assertEqual(regex.sub(r"(?V0)(x)?(y)?", r"\2-\1", "x"), '-x')
        self.assertEqual(regex.sub(r"(?V1)(x)?(y)?", r"\2-\1", "x"), '-x-')
        if sys.version_info >= (3, 7, 0):
            self.assertEqual(regex.sub(r"(?V0)(x)?(y)?", r"\2-\1", "y"), 'y--')
        else:
            self.assertEqual(regex.sub(r"(?V0)(x)?(y)?", r"\2-\1", "y"), 'y-')
        self.assertEqual(regex.sub(r"(?V1)(x)?(y)?", r"\2-\1", "y"), 'y--')

    def test_bug_10328 (self):
        # Issue 10328.
        pat = regex.compile(r'(?mV0)(?P<trailing_ws>[ \t]+\r*$)|(?P<no_final_newline>(?<=[^\n])\Z)')
        if sys.version_info >= (3, 7, 0):
            self.assertEqual(pat.subn(lambda m: '<' + m.lastgroup + '>',
              'foobar '), ('foobar<trailing_ws><no_final_newline>', 2))
        else:
            self.assertEqual(pat.subn(lambda m: '<' + m.lastgroup + '>',
              'foobar '), ('foobar<trailing_ws>', 1))
        self.assertEqual([m.group() for m in pat.finditer('foobar ')], [' ',
          ''])
        pat = regex.compile(r'(?mV1)(?P<trailing_ws>[ \t]+\r*$)|(?P<no_final_newline>(?<=[^\n])\Z)')
        self.assertEqual(pat.subn(lambda m: '<' + m.lastgroup + '>',
          'foobar '), ('foobar<trailing_ws><no_final_newline>', 2))
        self.assertEqual([m.group() for m in pat.finditer('foobar ')], [' ',
          ''])

    def test_overlapped(self):
        self.assertEqual(regex.findall(r"..", "abcde"), ['ab', 'cd'])
        self.assertEqual(regex.findall(r"..", "abcde", overlapped=True), ['ab',
          'bc', 'cd', 'de'])
        self.assertEqual(regex.findall(r"(?r)..", "abcde"), ['de', 'bc'])
        self.assertEqual(regex.findall(r"(?r)..", "abcde", overlapped=True),
          ['de', 'cd', 'bc', 'ab'])
        self.assertEqual(regex.findall(r"(.)(-)(.)", "a-b-c", overlapped=True),
          [("a", "-", "b"), ("b", "-", "c")])

        self.assertEqual([m[0] for m in regex.finditer(r"..", "abcde")], ['ab',
          'cd'])
        self.assertEqual([m[0] for m in regex.finditer(r"..", "abcde",
          overlapped=True)], ['ab', 'bc', 'cd', 'de'])
        self.assertEqual([m[0] for m in regex.finditer(r"(?r)..", "abcde")],
          ['de', 'bc'])
        self.assertEqual([m[0] for m in regex.finditer(r"(?r)..", "abcde",
          overlapped=True)], ['de', 'cd', 'bc', 'ab'])

        self.assertEqual([m.groups() for m in regex.finditer(r"(.)(-)(.)",
          "a-b-c", overlapped=True)], [("a", "-", "b"), ("b", "-", "c")])
        self.assertEqual([m.groups() for m in regex.finditer(r"(?r)(.)(-)(.)",
          "a-b-c", overlapped=True)], [("b", "-", "c"), ("a", "-", "b")])

    def test_splititer(self):
        self.assertEqual(regex.split(r",", "a,b,,c,"), ['a', 'b', '', 'c', ''])
        self.assertEqual([m for m in regex.splititer(r",", "a,b,,c,")], ['a',
          'b', '', 'c', ''])

    def test_grapheme(self):
        self.assertEqual(regex.match(r"\X", "\xE0").span(), (0, 1))
        self.assertEqual(regex.match(r"\X", "a\u0300").span(), (0, 2))

        self.assertEqual(regex.findall(r"\X",
          "a\xE0a\u0300e\xE9e\u0301"), ['a', '\xe0', 'a\u0300', 'e',
          '\xe9', 'e\u0301'])
        self.assertEqual(regex.findall(r"\X{3}",
          "a\xE0a\u0300e\xE9e\u0301"), ['a\xe0a\u0300', 'e\xe9e\u0301'])
        self.assertEqual(regex.findall(r"\X", "\r\r\n\u0301A\u0301"),
          ['\r', '\r\n', '\u0301', 'A\u0301'])

    def test_word_boundary(self):
        text = 'The quick ("brown") fox can\'t jump 32.3 feet, right?'
        self.assertEqual(regex.split(r'(?V1)\b', text), ['', 'The', ' ',
          'quick', ' ("', 'brown', '") ', 'fox', ' ', 'can', "'", 't',
          ' ', 'jump', ' ', '32', '.', '3', ' ', 'feet', ', ',
          'right', '?'])
        self.assertEqual(regex.split(r'(?V1w)\b', text), ['', 'The', ' ',
          'quick', ' ', '(', '"', 'brown', '"', ')', ' ', 'fox', ' ',
          "can't", ' ', 'jump', ' ', '32.3', ' ', 'feet', ',', ' ',
          'right', '?', ''])

        text = "The  fox"
        self.assertEqual(regex.split(r'(?V1)\b', text), ['', 'The', '  ',
          'fox', ''])
        self.assertEqual(regex.split(r'(?V1w)\b', text), ['', 'The', '  ',
          'fox', ''])

        text = "can't aujourd'hui l'objectif"
        self.assertEqual(regex.split(r'(?V1)\b', text), ['', 'can', "'",
          't', ' ', 'aujourd', "'", 'hui', ' ', 'l', "'", 'objectif',
          ''])
        self.assertEqual(regex.split(r'(?V1w)\b', text), ['', "can't", ' ',
          "aujourd'hui", ' ', "l'objectif", ''])

    def test_line_boundary(self):
        self.assertEqual(regex.findall(r".+", "Line 1\nLine 2\n"), ["Line 1",
          "Line 2"])
        self.assertEqual(regex.findall(r".+", "Line 1\rLine 2\r"),
          ["Line 1\rLine 2\r"])
        self.assertEqual(regex.findall(r".+", "Line 1\r\nLine 2\r\n"),
          ["Line 1\r", "Line 2\r"])
        self.assertEqual(regex.findall(r"(?w).+", "Line 1\nLine 2\n"),
          ["Line 1", "Line 2"])
        self.assertEqual(regex.findall(r"(?w).+", "Line 1\rLine 2\r"),
          ["Line 1", "Line 2"])
        self.assertEqual(regex.findall(r"(?w).+", "Line 1\r\nLine 2\r\n"),
          ["Line 1", "Line 2"])

        self.assertEqual(regex.search(r"^abc", "abc").start(), 0)
        self.assertEqual(regex.search(r"^abc", "\nabc"), None)
        self.assertEqual(regex.search(r"^abc", "\rabc"), None)
        self.assertEqual(regex.search(r"(?w)^abc", "abc").start(), 0)
        self.assertEqual(regex.search(r"(?w)^abc", "\nabc"), None)
        self.assertEqual(regex.search(r"(?w)^abc", "\rabc"), None)

        self.assertEqual(regex.search(r"abc$", "abc").start(), 0)
        self.assertEqual(regex.search(r"abc$", "abc\n").start(), 0)
        self.assertEqual(regex.search(r"abc$", "abc\r"), None)
        self.assertEqual(regex.search(r"(?w)abc$", "abc").start(), 0)
        self.assertEqual(regex.search(r"(?w)abc$", "abc\n").start(), 0)
        self.assertEqual(regex.search(r"(?w)abc$", "abc\r").start(), 0)

        self.assertEqual(regex.search(r"(?m)^abc", "abc").start(), 0)
        self.assertEqual(regex.search(r"(?m)^abc", "\nabc").start(), 1)
        self.assertEqual(regex.search(r"(?m)^abc", "\rabc"), None)
        self.assertEqual(regex.search(r"(?mw)^abc", "abc").start(), 0)
        self.assertEqual(regex.search(r"(?mw)^abc", "\nabc").start(), 1)
        self.assertEqual(regex.search(r"(?mw)^abc", "\rabc").start(), 1)

        self.assertEqual(regex.search(r"(?m)abc$", "abc").start(), 0)
        self.assertEqual(regex.search(r"(?m)abc$", "abc\n").start(), 0)
        self.assertEqual(regex.search(r"(?m)abc$", "abc\r"), None)
        self.assertEqual(regex.search(r"(?mw)abc$", "abc").start(), 0)
        self.assertEqual(regex.search(r"(?mw)abc$", "abc\n").start(), 0)
        self.assertEqual(regex.search(r"(?mw)abc$", "abc\r").start(), 0)

    def test_branch_reset(self):
        self.assertEqual(regex.match(r"(?:(a)|(b))(c)", "ac").groups(), ('a',
          None, 'c'))
        self.assertEqual(regex.match(r"(?:(a)|(b))(c)", "bc").groups(), (None,
          'b', 'c'))
        self.assertEqual(regex.match(r"(?:(?<a>a)|(?<b>b))(?<c>c)",
          "ac").groups(), ('a', None, 'c'))
        self.assertEqual(regex.match(r"(?:(?<a>a)|(?<b>b))(?<c>c)",
          "bc").groups(), (None, 'b', 'c'))

        self.assertEqual(regex.match(r"(?<a>a)(?:(?<b>b)|(?<c>c))(?<d>d)",
          "abd").groups(), ('a', 'b', None, 'd'))
        self.assertEqual(regex.match(r"(?<a>a)(?:(?<b>b)|(?<c>c))(?<d>d)",
          "acd").groups(), ('a', None, 'c', 'd'))
        self.assertEqual(regex.match(r"(a)(?:(b)|(c))(d)", "abd").groups(),
          ('a', 'b', None, 'd'))

        self.assertEqual(regex.match(r"(a)(?:(b)|(c))(d)", "acd").groups(),
          ('a', None, 'c', 'd'))
        self.assertEqual(regex.match(r"(a)(?|(b)|(b))(d)", "abd").groups(),
          ('a', 'b', 'd'))
        self.assertEqual(regex.match(r"(?|(?<a>a)|(?<b>b))(c)", "ac").groups(),
          ('a', None, 'c'))
        self.assertEqual(regex.match(r"(?|(?<a>a)|(?<b>b))(c)", "bc").groups(),
          (None, 'b', 'c'))
        self.assertEqual(regex.match(r"(?|(?<a>a)|(?<a>b))(c)", "ac").groups(),
          ('a', 'c'))

        self.assertEqual(regex.match(r"(?|(?<a>a)|(?<a>b))(c)", "bc").groups(),
          ('b', 'c'))

        self.assertEqual(regex.match(r"(?|(?<a>a)(?<b>b)|(?<b>c)(?<a>d))(e)",
          "abe").groups(), ('a', 'b', 'e'))
        self.assertEqual(regex.match(r"(?|(?<a>a)(?<b>b)|(?<b>c)(?<a>d))(e)",
          "cde").groups(), ('d', 'c', 'e'))
        self.assertEqual(regex.match(r"(?|(?<a>a)(?<b>b)|(?<b>c)(d))(e)",
          "abe").groups(), ('a', 'b', 'e'))
        self.assertEqual(regex.match(r"(?|(?<a>a)(?<b>b)|(?<b>c)(d))(e)",
          "cde").groups(), ('d', 'c', 'e'))
        self.assertEqual(regex.match(r"(?|(?<a>a)(?<b>b)|(c)(d))(e)",
          "abe").groups(), ('a', 'b', 'e'))
        self.assertEqual(regex.match(r"(?|(?<a>a)(?<b>b)|(c)(d))(e)",
          "cde").groups(), ('c', 'd', 'e'))

        # Hg issue 87: Allow duplicate names of groups
        self.assertEqual(regex.match(r"(?|(?<a>a)(?<b>b)|(c)(?<a>d))(e)",
          "abe").groups(), ("a", "b", "e"))
        self.assertEqual(regex.match(r"(?|(?<a>a)(?<b>b)|(c)(?<a>d))(e)",
          "abe").capturesdict(), {"a": ["a"], "b": ["b"]})
        self.assertEqual(regex.match(r"(?|(?<a>a)(?<b>b)|(c)(?<a>d))(e)",
          "cde").groups(), ("d", None, "e"))
        self.assertEqual(regex.match(r"(?|(?<a>a)(?<b>b)|(c)(?<a>d))(e)",
          "cde").capturesdict(), {"a": ["c", "d"], "b": []})

    def test_set(self):
        self.assertEqual(regex.match(r"[a]", "a").span(), (0, 1))
        self.assertEqual(regex.match(r"(?i)[a]", "A").span(), (0, 1))
        self.assertEqual(regex.match(r"[a-b]", r"a").span(), (0, 1))
        self.assertEqual(regex.match(r"(?i)[a-b]", r"A").span(), (0, 1))

        self.assertEqual(regex.sub(r"(?V0)([][])", r"-", "a[b]c"), "a-b-c")

        self.assertEqual(regex.findall(r"[\p{Alpha}]", "a0"), ["a"])
        self.assertEqual(regex.findall(r"(?i)[\p{Alpha}]", "A0"), ["A"])

        self.assertEqual(regex.findall(r"[a\p{Alpha}]", "ab0"), ["a", "b"])
        self.assertEqual(regex.findall(r"[a\P{Alpha}]", "ab0"), ["a", "0"])
        self.assertEqual(regex.findall(r"(?i)[a\p{Alpha}]", "ab0"), ["a",
          "b"])
        self.assertEqual(regex.findall(r"(?i)[a\P{Alpha}]", "ab0"), ["a",
          "0"])

        self.assertEqual(regex.findall(r"[a-b\p{Alpha}]", "abC0"), ["a",
          "b", "C"])
        self.assertEqual(regex.findall(r"(?i)[a-b\p{Alpha}]", "AbC0"), ["A",
          "b", "C"])

        self.assertEqual(regex.findall(r"[\p{Alpha}]", "a0"), ["a"])
        self.assertEqual(regex.findall(r"[\P{Alpha}]", "a0"), ["0"])
        self.assertEqual(regex.findall(r"[^\p{Alpha}]", "a0"), ["0"])
        self.assertEqual(regex.findall(r"[^\P{Alpha}]", "a0"), ["a"])

        self.assertEqual("".join(regex.findall(r"[^\d-h]", "a^b12c-h")),
          'a^bc')
        self.assertEqual("".join(regex.findall(r"[^\dh]", "a^b12c-h")),
          'a^bc-')
        self.assertEqual("".join(regex.findall(r"[^h\s\db]", "a^b 12c-h")),
          'a^c-')
        self.assertEqual("".join(regex.findall(r"[^b\w]", "a b")), ' ')
        self.assertEqual("".join(regex.findall(r"[^b\S]", "a b")), ' ')
        self.assertEqual("".join(regex.findall(r"[^8\d]", "a 1b2")), 'a b')

        all_chars = "".join(chr(c) for c in range(0x100))
        self.assertEqual(len(regex.findall(r"\p{ASCII}", all_chars)), 128)
        self.assertEqual(len(regex.findall(r"\p{Letter}", all_chars)),
          117)
        self.assertEqual(len(regex.findall(r"\p{Digit}", all_chars)), 10)

        # Set operators
        self.assertEqual(len(regex.findall(r"(?V1)[\p{ASCII}&&\p{Letter}]",
          all_chars)), 52)
        self.assertEqual(len(regex.findall(r"(?V1)[\p{ASCII}&&\p{Alnum}&&\p{Letter}]",
          all_chars)), 52)
        self.assertEqual(len(regex.findall(r"(?V1)[\p{ASCII}&&\p{Alnum}&&\p{Digit}]",
          all_chars)), 10)
        self.assertEqual(len(regex.findall(r"(?V1)[\p{ASCII}&&\p{Cc}]",
          all_chars)), 33)
        self.assertEqual(len(regex.findall(r"(?V1)[\p{ASCII}&&\p{Graph}]",
          all_chars)), 94)
        self.assertEqual(len(regex.findall(r"(?V1)[\p{ASCII}--\p{Cc}]",
          all_chars)), 95)
        self.assertEqual(len(regex.findall(r"[\p{Letter}\p{Digit}]",
          all_chars)), 127)
        self.assertEqual(len(regex.findall(r"(?V1)[\p{Letter}||\p{Digit}]",
          all_chars)), 127)
        self.assertEqual(len(regex.findall(r"\p{HexDigit}", all_chars)),
          22)
        self.assertEqual(len(regex.findall(r"(?V1)[\p{HexDigit}~~\p{Digit}]",
          all_chars)), 12)
        self.assertEqual(len(regex.findall(r"(?V1)[\p{Digit}~~\p{HexDigit}]",
          all_chars)), 12)

        self.assertEqual(repr(type(regex.compile(r"(?V0)([][-])"))),
          self.PATTERN_CLASS)
        self.assertEqual(regex.findall(r"(?V1)[[a-z]--[aei]]", "abc"), ["b",
          "c"])
        self.assertEqual(regex.findall(r"(?iV1)[[a-z]--[aei]]", "abc"), ["b",
          "c"])
        self.assertEqual(regex.findall(r"(?V1)[\w--a]","abc"), ["b", "c"])
        self.assertEqual(regex.findall(r"(?iV1)[\w--a]","abc"), ["b", "c"])

    def test_various(self):
        tests = [
            # Test ?P< and ?P= extensions.
            ('(?P<foo_123', '', '', regex.error, self.MISSING_GT),      # Unterminated group identifier.
            ('(?P<1>a)', '', '', regex.error, self.BAD_GROUP_NAME),     # Begins with a digit.
            ('(?P<!>a)', '', '', regex.error, self.BAD_GROUP_NAME),     # Begins with an illegal char.
            ('(?P<foo!>a)', '', '', regex.error, self.BAD_GROUP_NAME),  # Begins with an illegal char.

            # Same tests, for the ?P= form.
            ('(?P<foo_123>a)(?P=foo_123', 'aa', '', regex.error,
              self.MISSING_RPAREN),
            ('(?P<foo_123>a)(?P=1)', 'aa', '1', ascii('a')),
            ('(?P<foo_123>a)(?P=0)', 'aa', '', regex.error,
              self.BAD_GROUP_NAME),
            ('(?P<foo_123>a)(?P=-1)', 'aa', '', regex.error,
              self.BAD_GROUP_NAME),
            ('(?P<foo_123>a)(?P=!)', 'aa', '', regex.error,
              self.BAD_GROUP_NAME),
            ('(?P<foo_123>a)(?P=foo_124)', 'aa', '', regex.error,
              self.UNKNOWN_GROUP),  # Backref to undefined group.

            ('(?P<foo_123>a)', 'a', '1', ascii('a')),
            ('(?P<foo_123>a)(?P=foo_123)', 'aa', '1', ascii('a')),

            # Mal-formed \g in pattern treated as literal for compatibility.
            (r'(?<foo_123>a)\g<foo_123', 'aa', '', ascii(None)),
            (r'(?<foo_123>a)\g<1>', 'aa', '1', ascii('a')),
            (r'(?<foo_123>a)\g<!>', 'aa', '', ascii(None)),
            (r'(?<foo_123>a)\g<foo_124>', 'aa', '', regex.error,
              self.UNKNOWN_GROUP),  # Backref to undefined group.

            ('(?<foo_123>a)', 'a', '1', ascii('a')),
            (r'(?<foo_123>a)\g<foo_123>', 'aa', '1', ascii('a')),

            # Test octal escapes.
            ('\\1', 'a', '', regex.error, self.INVALID_GROUP_REF),    # Backreference.
            ('[\\1]', '\1', '0', "'\\x01'"),  # Character.
            ('\\09', chr(0) + '9', '0', ascii(chr(0) + '9')),
            ('\\141', 'a', '0', ascii('a')),
            ('(a)(b)(c)(d)(e)(f)(g)(h)(i)(j)(k)(l)\\119', 'abcdefghijklk9',
              '0,11', ascii(('abcdefghijklk9', 'k'))),

            # Test \0 is handled everywhere.
            (r'\0', '\0', '0', ascii('\0')),
            (r'[\0a]', '\0', '0', ascii('\0')),
            (r'[a\0]', '\0', '0', ascii('\0')),
            (r'[^a\0]', '\0', '', ascii(None)),

            # Test various letter escapes.
            (r'\a[\b]\f\n\r\t\v', '\a\b\f\n\r\t\v', '0',
              ascii('\a\b\f\n\r\t\v')),
            (r'[\a][\b][\f][\n][\r][\t][\v]', '\a\b\f\n\r\t\v', '0',
              ascii('\a\b\f\n\r\t\v')),
            (r'\xff', '\377', '0', ascii(chr(255))),

            # New \x semantics.
            (r'\x00ffffffffffffff', '\377', '', ascii(None)),
            (r'\x00f', '\017', '', ascii(None)),
            (r'\x00fe', '\376', '', ascii(None)),

            (r'\x00ff', '\377', '', ascii(None)),
            (r'\t\n\v\r\f\a\g', '\t\n\v\r\f\ag', '0', ascii('\t\n\v\r\f\ag')),
            ('\t\n\v\r\f\a\\g', '\t\n\v\r\f\ag', '0', ascii('\t\n\v\r\f\ag')),
            (r'\t\n\v\r\f\a', '\t\n\v\r\f\a', '0', ascii(chr(9) + chr(10) +
              chr(11) + chr(13) + chr(12) + chr(7))),
            (r'[\t][\n][\v][\r][\f][\b]', '\t\n\v\r\f\b', '0',
              ascii('\t\n\v\r\f\b')),

            (r"^\w+=(\\[\000-\277]|[^\n\\])*",
              "SRC=eval.c g.c blah blah blah \\\\\n\tapes.c", '0',
              ascii("SRC=eval.c g.c blah blah blah \\\\")),

            # Test that . only matches \n in DOTALL mode.
            ('a.b', 'acb', '0', ascii('acb')),
            ('a.b', 'a\nb', '', ascii(None)),
            ('a.*b', 'acc\nccb', '', ascii(None)),
            ('a.{4,5}b', 'acc\nccb', '', ascii(None)),
            ('a.b', 'a\rb', '0', ascii('a\rb')),
            # Changed to positional flags in regex 2023.12.23.
            ('a.b(?s)', 'a\nb', '', ascii(None)),
            ('(?s)a.b', 'a\nb', '0', ascii('a\nb')),
            ('a.*(?s)b', 'acc\nccb', '', ascii(None)),
            ('(?s)a.*b', 'acc\nccb', '0', ascii('acc\nccb')),
            ('(?s)a.{4,5}b', 'acc\nccb', '0', ascii('acc\nccb')),

            (')', '', '', regex.error, self.TRAILING_CHARS),           # Unmatched right bracket.
            ('', '', '0', "''"),    # Empty pattern.
            ('abc', 'abc', '0', ascii('abc')),
            ('abc', 'xbc', '', ascii(None)),
            ('abc', 'axc', '', ascii(None)),
            ('abc', 'abx', '', ascii(None)),
            ('abc', 'xabcy', '0', ascii('abc')),
            ('abc', 'ababc', '0', ascii('abc')),
            ('ab*c', 'abc', '0', ascii('abc')),
            ('ab*bc', 'abc', '0', ascii('abc')),

            ('ab*bc', 'abbc', '0', ascii('abbc')),
            ('ab*bc', 'abbbbc', '0', ascii('abbbbc')),
            ('ab+bc', 'abbc', '0', ascii('abbc')),
            ('ab+bc', 'abc', '', ascii(None)),
            ('ab+bc', 'abq', '', ascii(None)),
            ('ab+bc', 'abbbbc', '0', ascii('abbbbc')),
            ('ab?bc', 'abbc', '0', ascii('abbc')),
            ('ab?bc', 'abc', '0', ascii('abc')),
            ('ab?bc', 'abbbbc', '', ascii(None)),
            ('ab?c', 'abc', '0', ascii('abc')),

            ('^abc$', 'abc', '0', ascii('abc')),
            ('^abc$', 'abcc', '', ascii(None)),
            ('^abc', 'abcc', '0', ascii('abc')),
            ('^abc$', 'aabc', '', ascii(None)),
            ('abc$', 'aabc', '0', ascii('abc')),
            ('^', 'abc', '0', ascii('')),
            ('$', 'abc', '0', ascii('')),
            ('a.c', 'abc', '0', ascii('abc')),
            ('a.c', 'axc', '0', ascii('axc')),
            ('a.*c', 'axyzc', '0', ascii('axyzc')),

            ('a.*c', 'axyzd', '', ascii(None)),
            ('a[bc]d', 'abc', '', ascii(None)),
            ('a[bc]d', 'abd', '0', ascii('abd')),
            ('a[b-d]e', 'abd', '', ascii(None)),
            ('a[b-d]e', 'ace', '0', ascii('ace')),
            ('a[b-d]', 'aac', '0', ascii('ac')),
            ('a[-b]', 'a-', '0', ascii('a-')),
            ('a[\\-b]', 'a-', '0', ascii('a-')),
            ('a[b-]', 'a-', '0', ascii('a-')),
            ('a[]b', '-', '', regex.error, self.BAD_SET),

            ('a[', '-', '', regex.error, self.BAD_SET),
            ('a\\', '-', '', regex.error, self.BAD_ESCAPE),
            ('abc)', '-', '', regex.error, self.TRAILING_CHARS),
            ('(abc', '-', '', regex.error, self.MISSING_RPAREN),
            ('a]', 'a]', '0', ascii('a]')),
            ('a[]]b', 'a]b', '0', ascii('a]b')),
            ('a[]]b', 'a]b', '0', ascii('a]b')),
            ('a[^bc]d', 'aed', '0', ascii('aed')),
            ('a[^bc]d', 'abd', '', ascii(None)),
            ('a[^-b]c', 'adc', '0', ascii('adc')),

            ('a[^-b]c', 'a-c', '', ascii(None)),
            ('a[^]b]c', 'a]c', '', ascii(None)),
            ('a[^]b]c', 'adc', '0', ascii('adc')),
            ('\\ba\\b', 'a-', '0', ascii('a')),
            ('\\ba\\b', '-a', '0', ascii('a')),
            ('\\ba\\b', '-a-', '0', ascii('a')),
            ('\\by\\b', 'xy', '', ascii(None)),
            ('\\by\\b', 'yz', '', ascii(None)),
            ('\\by\\b', 'xyz', '', ascii(None)),
            ('x\\b', 'xyz', '', ascii(None)),

            ('x\\B', 'xyz', '0', ascii('x')),
            ('\\Bz', 'xyz', '0', ascii('z')),
            ('z\\B', 'xyz', '', ascii(None)),
            ('\\Bx', 'xyz', '', ascii(None)),
            ('\\Ba\\B', 'a-', '', ascii(None)),
            ('\\Ba\\B', '-a', '', ascii(None)),
            ('\\Ba\\B', '-a-', '', ascii(None)),
            ('\\By\\B', 'xy', '', ascii(None)),
            ('\\By\\B', 'yz', '', ascii(None)),
            ('\\By\\b', 'xy', '0', ascii('y')),

            ('\\by\\B', 'yz', '0', ascii('y')),
            ('\\By\\B', 'xyz', '0', ascii('y')),
            ('ab|cd', 'abc', '0', ascii('ab')),
            ('ab|cd', 'abcd', '0', ascii('ab')),
            ('()ef', 'def', '0,1', ascii(('ef', ''))),
            ('$b', 'b', '', ascii(None)),
            ('a\\(b', 'a(b', '', ascii(('a(b',))),
            ('a\\(*b', 'ab', '0', ascii('ab')),
            ('a\\(*b', 'a((b', '0', ascii('a((b')),
            ('a\\\\b', 'a\\b', '0', ascii('a\\b')),

            ('((a))', 'abc', '0,1,2', ascii(('a', 'a', 'a'))),
            ('(a)b(c)', 'abc', '0,1,2', ascii(('abc', 'a', 'c'))),
            ('a+b+c', 'aabbabc', '0', ascii('abc')),
            ('(a+|b)*', 'ab', '0,1', ascii(('ab', 'b'))),
            ('(a+|b)+', 'ab', '0,1', ascii(('ab', 'b'))),
            ('(a+|b)?', 'ab', '0,1', ascii(('a', 'a'))),
            (')(', '-', '', regex.error, self.TRAILING_CHARS),
            ('[^ab]*', 'cde', '0', ascii('cde')),
            ('abc', '', '', ascii(None)),
            ('a*', '', '0', ascii('')),

            ('a|b|c|d|e', 'e', '0', ascii('e')),
            ('(a|b|c|d|e)f', 'ef', '0,1', ascii(('ef', 'e'))),
            ('abcd*efg', 'abcdefg', '0', ascii('abcdefg')),
            ('ab*', 'xabyabbbz', '0', ascii('ab')),
            ('ab*', 'xayabbbz', '0', ascii('a')),
            ('(ab|cd)e', 'abcde', '0,1', ascii(('cde', 'cd'))),
            ('[abhgefdc]ij', 'hij', '0', ascii('hij')),
            ('^(ab|cd)e', 'abcde', '', ascii(None)),
            ('(abc|)ef', 'abcdef', '0,1', ascii(('ef', ''))),
            ('(a|b)c*d', 'abcd', '0,1', ascii(('bcd', 'b'))),

            ('(ab|ab*)bc', 'abc', '0,1', ascii(('abc', 'a'))),
            ('a([bc]*)c*', 'abc', '0,1', ascii(('abc', 'bc'))),
            ('a([bc]*)(c*d)', 'abcd', '0,1,2', ascii(('abcd', 'bc', 'd'))),
            ('a([bc]+)(c*d)', 'abcd', '0,1,2', ascii(('abcd', 'bc', 'd'))),
            ('a([bc]*)(c+d)', 'abcd', '0,1,2', ascii(('abcd', 'b', 'cd'))),
            ('a[bcd]*dcdcde', 'adcdcde', '0', ascii('adcdcde')),
            ('a[bcd]+dcdcde', 'adcdcde', '', ascii(None)),
            ('(ab|a)b*c', 'abc', '0,1', ascii(('abc', 'ab'))),
            ('((a)(b)c)(d)', 'abcd', '1,2,3,4', ascii(('abc', 'a', 'b', 'd'))),
            ('[a-zA-Z_][a-zA-Z0-9_]*', 'alpha', '0', ascii('alpha')),

            ('^a(bc+|b[eh])g|.h$', 'abh', '0,1', ascii(('bh', None))),
            ('(bc+d$|ef*g.|h?i(j|k))', 'effgz', '0,1,2', ascii(('effgz',
              'effgz', None))),
            ('(bc+d$|ef*g.|h?i(j|k))', 'ij', '0,1,2', ascii(('ij', 'ij',
              'j'))),
            ('(bc+d$|ef*g.|h?i(j|k))', 'effg', '', ascii(None)),
            ('(bc+d$|ef*g.|h?i(j|k))', 'bcdd', '', ascii(None)),
            ('(bc+d$|ef*g.|h?i(j|k))', 'reffgz', '0,1,2', ascii(('effgz',
              'effgz', None))),
            ('(((((((((a)))))))))', 'a', '0', ascii('a')),
            ('multiple words of text', 'uh-uh', '', ascii(None)),
            ('multiple words', 'multiple words, yeah', '0',
              ascii('multiple words')),
            ('(.*)c(.*)', 'abcde', '0,1,2', ascii(('abcde', 'ab', 'de'))),

            ('\\((.*), (.*)\\)', '(a, b)', '2,1', ascii(('b', 'a'))),
            ('[k]', 'ab', '', ascii(None)),
            ('a[-]?c', 'ac', '0', ascii('ac')),
            ('(abc)\\1', 'abcabc', '1', ascii('abc')),
            ('([a-c]*)\\1', 'abcabc', '1', ascii('abc')),
            ('^(.+)?B', 'AB', '1', ascii('A')),
            ('(a+).\\1$', 'aaaaa', '0,1', ascii(('aaaaa', 'aa'))),
            ('^(a+).\\1$', 'aaaa', '', ascii(None)),
            ('(abc)\\1', 'abcabc', '0,1', ascii(('abcabc', 'abc'))),
            ('([a-c]+)\\1', 'abcabc', '0,1', ascii(('abcabc', 'abc'))),

            ('(a)\\1', 'aa', '0,1', ascii(('aa', 'a'))),
            ('(a+)\\1', 'aa', '0,1', ascii(('aa', 'a'))),
            ('(a+)+\\1', 'aa', '0,1', ascii(('aa', 'a'))),
            ('(a).+\\1', 'aba', '0,1', ascii(('aba', 'a'))),
            ('(a)ba*\\1', 'aba', '0,1', ascii(('aba', 'a'))),
            ('(aa|a)a\\1$', 'aaa', '0,1', ascii(('aaa', 'a'))),
            ('(a|aa)a\\1$', 'aaa', '0,1', ascii(('aaa', 'a'))),
            ('(a+)a\\1$', 'aaa', '0,1', ascii(('aaa', 'a'))),
            ('([abc]*)\\1', 'abcabc', '0,1', ascii(('abcabc', 'abc'))),
            ('(a)(b)c|ab', 'ab', '0,1,2', ascii(('ab', None, None))),

            ('(a)+x', 'aaax', '0,1', ascii(('aaax', 'a'))),
            ('([ac])+x', 'aacx', '0,1', ascii(('aacx', 'c'))),
            ('([^/]*/)*sub1/', 'd:msgs/tdir/sub1/trial/away.cpp', '0,1',
              ascii(('d:msgs/tdir/sub1/', 'tdir/'))),
            ('([^.]*)\\.([^:]*):[T ]+(.*)', 'track1.title:TBlah blah blah',
              '0,1,2,3', ascii(('track1.title:TBlah blah blah', 'track1',
              'title', 'Blah blah blah'))),
            ('([^N]*N)+', 'abNNxyzN', '0,1', ascii(('abNNxyzN', 'xyzN'))),
            ('([^N]*N)+', 'abNNxyz', '0,1', ascii(('abNN', 'N'))),
            ('([abc]*)x', 'abcx', '0,1', ascii(('abcx', 'abc'))),
            ('([abc]*)x', 'abc', '', ascii(None)),
            ('([xyz]*)x', 'abcx', '0,1', ascii(('x', ''))),
            ('(a)+b|aac', 'aac', '0,1', ascii(('aac', None))),

            # Test symbolic groups.
            ('(?P<i d>aaa)a', 'aaaa', '', regex.error, self.BAD_GROUP_NAME),
            ('(?P<id>aaa)a', 'aaaa', '0,id', ascii(('aaaa', 'aaa'))),
            ('(?P<id>aa)(?P=id)', 'aaaa', '0,id', ascii(('aaaa', 'aa'))),
            ('(?P<id>aa)(?P=xd)', 'aaaa', '', regex.error, self.UNKNOWN_GROUP),

            # Character properties.
            (r"\g", "g", '0', ascii('g')),
            (r"\g<1>", "g", '', regex.error, self.INVALID_GROUP_REF),
            (r"(.)\g<1>", "gg", '0', ascii('gg')),
            (r"(.)\g<1>", "gg", '', ascii(('gg', 'g'))),
            (r"\N", "N", '0', ascii('N')),
            (r"\N{LATIN SMALL LETTER A}", "a", '0', ascii('a')),
            (r"\p", "p", '0', ascii('p')),
            (r"\p{Ll}", "a", '0', ascii('a')),
            (r"\P", "P", '0', ascii('P')),
            (r"\P{Lu}", "p", '0', ascii('p')),

            # All tests from Perl.
            ('abc', 'abc', '0', ascii('abc')),
            ('abc', 'xbc', '', ascii(None)),
            ('abc', 'axc', '', ascii(None)),
            ('abc', 'abx', '', ascii(None)),
            ('abc', 'xabcy', '0', ascii('abc')),
            ('abc', 'ababc', '0', ascii('abc')),

            ('ab*c', 'abc', '0', ascii('abc')),
            ('ab*bc', 'abc', '0', ascii('abc')),
            ('ab*bc', 'abbc', '0', ascii('abbc')),
            ('ab*bc', 'abbbbc', '0', ascii('abbbbc')),
            ('ab{0,}bc', 'abbbbc', '0', ascii('abbbbc')),
            ('ab+bc', 'abbc', '0', ascii('abbc')),
            ('ab+bc', 'abc', '', ascii(None)),
            ('ab+bc', 'abq', '', ascii(None)),
            ('ab{1,}bc', 'abq', '', ascii(None)),
            ('ab+bc', 'abbbbc', '0', ascii('abbbbc')),

            ('ab{1,}bc', 'abbbbc', '0', ascii('abbbbc')),
            ('ab{1,3}bc', 'abbbbc', '0', ascii('abbbbc')),
            ('ab{3,4}bc', 'abbbbc', '0', ascii('abbbbc')),
            ('ab{4,5}bc', 'abbbbc', '', ascii(None)),
            ('ab?bc', 'abbc', '0', ascii('abbc')),
            ('ab?bc', 'abc', '0', ascii('abc')),
            ('ab{0,1}bc', 'abc', '0', ascii('abc')),
            ('ab?bc', 'abbbbc', '', ascii(None)),
            ('ab?c', 'abc', '0', ascii('abc')),
            ('ab{0,1}c', 'abc', '0', ascii('abc')),

            ('^abc$', 'abc', '0', ascii('abc')),
            ('^abc$', 'abcc', '', ascii(None)),
            ('^abc', 'abcc', '0', ascii('abc')),
            ('^abc$', 'aabc', '', ascii(None)),
            ('abc$', 'aabc', '0', ascii('abc')),
            ('^', 'abc', '0', ascii('')),
            ('$', 'abc', '0', ascii('')),
            ('a.c', 'abc', '0', ascii('abc')),
            ('a.c', 'axc', '0', ascii('axc')),
            ('a.*c', 'axyzc', '0', ascii('axyzc')),

            ('a.*c', 'axyzd', '', ascii(None)),
            ('a[bc]d', 'abc', '', ascii(None)),
            ('a[bc]d', 'abd', '0', ascii('abd')),
            ('a[b-d]e', 'abd', '', ascii(None)),
            ('a[b-d]e', 'ace', '0', ascii('ace')),
            ('a[b-d]', 'aac', '0', ascii('ac')),
            ('a[-b]', 'a-', '0', ascii('a-')),
            ('a[b-]', 'a-', '0', ascii('a-')),
            ('a[b-a]', '-', '', regex.error, self.BAD_CHAR_RANGE),
            ('a[]b', '-', '', regex.error, self.BAD_SET),

            ('a[', '-', '', regex.error, self.BAD_SET),
            ('a]', 'a]', '0', ascii('a]')),
            ('a[]]b', 'a]b', '0', ascii('a]b')),
            ('a[^bc]d', 'aed', '0', ascii('aed')),
            ('a[^bc]d', 'abd', '', ascii(None)),
            ('a[^-b]c', 'adc', '0', ascii('adc')),
            ('a[^-b]c', 'a-c', '', ascii(None)),
            ('a[^]b]c', 'a]c', '', ascii(None)),
            ('a[^]b]c', 'adc', '0', ascii('adc')),
            ('ab|cd', 'abc', '0', ascii('ab')),

            ('ab|cd', 'abcd', '0', ascii('ab')),
            ('()ef', 'def', '0,1', ascii(('ef', ''))),
            ('*a', '-', '', regex.error, self.NOTHING_TO_REPEAT),
            ('(*)b', '-', '', regex.error, self.NOTHING_TO_REPEAT),
            ('$b', 'b', '', ascii(None)),
            ('a\\', '-', '', regex.error, self.BAD_ESCAPE),
            ('a\\(b', 'a(b', '', ascii(('a(b',))),
            ('a\\(*b', 'ab', '0', ascii('ab')),
            ('a\\(*b', 'a((b', '0', ascii('a((b')),
            ('a\\\\b', 'a\\b', '0', ascii('a\\b')),

            ('abc)', '-', '', regex.error, self.TRAILING_CHARS),
            ('(abc', '-', '', regex.error, self.MISSING_RPAREN),
            ('((a))', 'abc', '0,1,2', ascii(('a', 'a', 'a'))),
            ('(a)b(c)', 'abc', '0,1,2', ascii(('abc', 'a', 'c'))),
            ('a+b+c', 'aabbabc', '0', ascii('abc')),
            ('a{1,}b{1,}c', 'aabbabc', '0', ascii('abc')),
            ('a**', '-', '', regex.error, self.MULTIPLE_REPEAT),
            ('a.+?c', 'abcabc', '0', ascii('abc')),
            ('(a+|b)*', 'ab', '0,1', ascii(('ab', 'b'))),
            ('(a+|b){0,}', 'ab', '0,1', ascii(('ab', 'b'))),

            ('(a+|b)+', 'ab', '0,1', ascii(('ab', 'b'))),
            ('(a+|b){1,}', 'ab', '0,1', ascii(('ab', 'b'))),
            ('(a+|b)?', 'ab', '0,1', ascii(('a', 'a'))),
            ('(a+|b){0,1}', 'ab', '0,1', ascii(('a', 'a'))),
            (')(', '-', '', regex.error, self.TRAILING_CHARS),
            ('[^ab]*', 'cde', '0', ascii('cde')),
            ('abc', '', '', ascii(None)),
            ('a*', '', '0', ascii('')),
            ('([abc])*d', 'abbbcd', '0,1', ascii(('abbbcd', 'c'))),
            ('([abc])*bcd', 'abcd', '0,1', ascii(('abcd', 'a'))),

            ('a|b|c|d|e', 'e', '0', ascii('e')),
            ('(a|b|c|d|e)f', 'ef', '0,1', ascii(('ef', 'e'))),
            ('abcd*efg', 'abcdefg', '0', ascii('abcdefg')),
            ('ab*', 'xabyabbbz', '0', ascii('ab')),
            ('ab*', 'xayabbbz', '0', ascii('a')),
            ('(ab|cd)e', 'abcde', '0,1', ascii(('cde', 'cd'))),
            ('[abhgefdc]ij', 'hij', '0', ascii('hij')),
            ('^(ab|cd)e', 'abcde', '', ascii(None)),
            ('(abc|)ef', 'abcdef', '0,1', ascii(('ef', ''))),
            ('(a|b)c*d', 'abcd', '0,1', ascii(('bcd', 'b'))),

            ('(ab|ab*)bc', 'abc', '0,1', ascii(('abc', 'a'))),
            ('a([bc]*)c*', 'abc', '0,1', ascii(('abc', 'bc'))),
            ('a([bc]*)(c*d)', 'abcd', '0,1,2', ascii(('abcd', 'bc', 'd'))),
            ('a([bc]+)(c*d)', 'abcd', '0,1,2', ascii(('abcd', 'bc', 'd'))),
            ('a([bc]*)(c+d)', 'abcd', '0,1,2', ascii(('abcd', 'b', 'cd'))),
            ('a[bcd]*dcdcde', 'adcdcde', '0', ascii('adcdcde')),
            ('a[bcd]+dcdcde', 'adcdcde', '', ascii(None)),
            ('(ab|a)b*c', 'abc', '0,1', ascii(('abc', 'ab'))),
            ('((a)(b)c)(d)', 'abcd', '1,2,3,4', ascii(('abc', 'a', 'b', 'd'))),
            ('[a-zA-Z_][a-zA-Z0-9_]*', 'alpha', '0', ascii('alpha')),

            ('^a(bc+|b[eh])g|.h$', 'abh', '0,1', ascii(('bh', None))),
            ('(bc+d$|ef*g.|h?i(j|k))', 'effgz', '0,1,2', ascii(('effgz',
              'effgz', None))),
            ('(bc+d$|ef*g.|h?i(j|k))', 'ij', '0,1,2', ascii(('ij', 'ij',
              'j'))),
            ('(bc+d$|ef*g.|h?i(j|k))', 'effg', '', ascii(None)),
            ('(bc+d$|ef*g.|h?i(j|k))', 'bcdd', '', ascii(None)),
            ('(bc+d$|ef*g.|h?i(j|k))', 'reffgz', '0,1,2', ascii(('effgz',
              'effgz', None))),
            ('((((((((((a))))))))))', 'a', '10', ascii('a')),
            ('((((((((((a))))))))))\\10', 'aa', '0', ascii('aa')),

            # Python does not have the same rules for \\41 so this is a syntax error
            #    ('((((((((((a))))))))))\\41', 'aa', '', ascii(None)),
            #    ('((((((((((a))))))))))\\41', 'a!', '0', ascii('a!')),
            ('((((((((((a))))))))))\\41', '', '', regex.error,
              self.INVALID_GROUP_REF),
            ('(?i)((((((((((a))))))))))\\41', '', '', regex.error,
              self.INVALID_GROUP_REF),

            ('(((((((((a)))))))))', 'a', '0', ascii('a')),
            ('multiple words of text', 'uh-uh', '', ascii(None)),
            ('multiple words', 'multiple words, yeah', '0',
              ascii('multiple words')),
            ('(.*)c(.*)', 'abcde', '0,1,2', ascii(('abcde', 'ab', 'de'))),
            ('\\((.*), (.*)\\)', '(a, b)', '2,1', ascii(('b', 'a'))),
            ('[k]', 'ab', '', ascii(None)),
            ('a[-]?c', 'ac', '0', ascii('ac')),
            ('(abc)\\1', 'abcabc', '1', ascii('abc')),
            ('([a-c]*)\\1', 'abcabc', '1', ascii('abc')),
            ('(?i)abc', 'ABC', '0', ascii('ABC')),

            ('(?i)abc', 'XBC', '', ascii(None)),
            ('(?i)abc', 'AXC', '', ascii(None)),
            ('(?i)abc', 'ABX', '', ascii(None)),
            ('(?i)abc', 'XABCY', '0', ascii('ABC')),
            ('(?i)abc', 'ABABC', '0', ascii('ABC')),
            ('(?i)ab*c', 'ABC', '0', ascii('ABC')),
            ('(?i)ab*bc', 'ABC', '0', ascii('ABC')),
            ('(?i)ab*bc', 'ABBC', '0', ascii('ABBC')),
            ('(?i)ab*?bc', 'ABBBBC', '0', ascii('ABBBBC')),
            ('(?i)ab{0,}?bc', 'ABBBBC', '0', ascii('ABBBBC')),

            ('(?i)ab+?bc', 'ABBC', '0', ascii('ABBC')),
            ('(?i)ab+bc', 'ABC', '', ascii(None)),
            ('(?i)ab+bc', 'ABQ', '', ascii(None)),
            ('(?i)ab{1,}bc', 'ABQ', '', ascii(None)),
            ('(?i)ab+bc', 'ABBBBC', '0', ascii('ABBBBC')),
            ('(?i)ab{1,}?bc', 'ABBBBC', '0', ascii('ABBBBC')),
            ('(?i)ab{1,3}?bc', 'ABBBBC', '0', ascii('ABBBBC')),
            ('(?i)ab{3,4}?bc', 'ABBBBC', '0', ascii('ABBBBC')),
            ('(?i)ab{4,5}?bc', 'ABBBBC', '', ascii(None)),
            ('(?i)ab??bc', 'ABBC', '0', ascii('ABBC')),

            ('(?i)ab??bc', 'ABC', '0', ascii('ABC')),
            ('(?i)ab{0,1}?bc', 'ABC', '0', ascii('ABC')),
            ('(?i)ab??bc', 'ABBBBC', '', ascii(None)),
            ('(?i)ab??c', 'ABC', '0', ascii('ABC')),
            ('(?i)ab{0,1}?c', 'ABC', '0', ascii('ABC')),
            ('(?i)^abc$', 'ABC', '0', ascii('ABC')),
            ('(?i)^abc$', 'ABCC', '', ascii(None)),
            ('(?i)^abc', 'ABCC', '0', ascii('ABC')),
            ('(?i)^abc$', 'AABC', '', ascii(None)),
            ('(?i)abc$', 'AABC', '0', ascii('ABC')),

            ('(?i)^', 'ABC', '0', ascii('')),
            ('(?i)$', 'ABC', '0', ascii('')),
            ('(?i)a.c', 'ABC', '0', ascii('ABC')),
            ('(?i)a.c', 'AXC', '0', ascii('AXC')),
            ('(?i)a.*?c', 'AXYZC', '0', ascii('AXYZC')),
            ('(?i)a.*c', 'AXYZD', '', ascii(None)),
            ('(?i)a[bc]d', 'ABC', '', ascii(None)),
            ('(?i)a[bc]d', 'ABD', '0', ascii('ABD')),
            ('(?i)a[b-d]e', 'ABD', '', ascii(None)),
            ('(?i)a[b-d]e', 'ACE', '0', ascii('ACE')),

            ('(?i)a[b-d]', 'AAC', '0', ascii('AC')),
            ('(?i)a[-b]', 'A-', '0', ascii('A-')),
            ('(?i)a[b-]', 'A-', '0', ascii('A-')),
            ('(?i)a[b-a]', '-', '', regex.error, self.BAD_CHAR_RANGE),
            ('(?i)a[]b', '-', '', regex.error, self.BAD_SET),
            ('(?i)a[', '-', '', regex.error, self.BAD_SET),
            ('(?i)a]', 'A]', '0', ascii('A]')),
            ('(?i)a[]]b', 'A]B', '0', ascii('A]B')),
            ('(?i)a[^bc]d', 'AED', '0', ascii('AED')),
            ('(?i)a[^bc]d', 'ABD', '', ascii(None)),

            ('(?i)a[^-b]c', 'ADC', '0', ascii('ADC')),
            ('(?i)a[^-b]c', 'A-C', '', ascii(None)),
            ('(?i)a[^]b]c', 'A]C', '', ascii(None)),
            ('(?i)a[^]b]c', 'ADC', '0', ascii('ADC')),
            ('(?i)ab|cd', 'ABC', '0', ascii('AB')),
            ('(?i)ab|cd', 'ABCD', '0', ascii('AB')),
            ('(?i)()ef', 'DEF', '0,1', ascii(('EF', ''))),
            ('(?i)*a', '-', '', regex.error, self.NOTHING_TO_REPEAT),
            ('(?i)(*)b', '-', '', regex.error, self.NOTHING_TO_REPEAT),
            ('(?i)$b', 'B', '', ascii(None)),

            ('(?i)a\\', '-', '', regex.error, self.BAD_ESCAPE),
            ('(?i)a\\(b', 'A(B', '', ascii(('A(B',))),
            ('(?i)a\\(*b', 'AB', '0', ascii('AB')),
            ('(?i)a\\(*b', 'A((B', '0', ascii('A((B')),
            ('(?i)a\\\\b', 'A\\B', '0', ascii('A\\B')),
            ('(?i)abc)', '-', '', regex.error, self.TRAILING_CHARS),
            ('(?i)(abc', '-', '', regex.error, self.MISSING_RPAREN),
            ('(?i)((a))', 'ABC', '0,1,2', ascii(('A', 'A', 'A'))),
            ('(?i)(a)b(c)', 'ABC', '0,1,2', ascii(('ABC', 'A', 'C'))),
            ('(?i)a+b+c', 'AABBABC', '0', ascii('ABC')),

            ('(?i)a{1,}b{1,}c', 'AABBABC', '0', ascii('ABC')),
            ('(?i)a**', '-', '', regex.error, self.MULTIPLE_REPEAT),
            ('(?i)a.+?c', 'ABCABC', '0', ascii('ABC')),
            ('(?i)a.*?c', 'ABCABC', '0', ascii('ABC')),
            ('(?i)a.{0,5}?c', 'ABCABC', '0', ascii('ABC')),
            ('(?i)(a+|b)*', 'AB', '0,1', ascii(('AB', 'B'))),
            ('(?i)(a+|b){0,}', 'AB', '0,1', ascii(('AB', 'B'))),
            ('(?i)(a+|b)+', 'AB', '0,1', ascii(('AB', 'B'))),
            ('(?i)(a+|b){1,}', 'AB', '0,1', ascii(('AB', 'B'))),
            ('(?i)(a+|b)?', 'AB', '0,1', ascii(('A', 'A'))),

            ('(?i)(a+|b){0,1}', 'AB', '0,1', ascii(('A', 'A'))),
            ('(?i)(a+|b){0,1}?', 'AB', '0,1', ascii(('', None))),
            ('(?i))(', '-', '', regex.error, self.TRAILING_CHARS),
            ('(?i)[^ab]*', 'CDE', '0', ascii('CDE')),
            ('(?i)abc', '', '', ascii(None)),
            ('(?i)a*', '', '0', ascii('')),
            ('(?i)([abc])*d', 'ABBBCD', '0,1', ascii(('ABBBCD', 'C'))),
            ('(?i)([abc])*bcd', 'ABCD', '0,1', ascii(('ABCD', 'A'))),
            ('(?i)a|b|c|d|e', 'E', '0', ascii('E')),
            ('(?i)(a|b|c|d|e)f', 'EF', '0,1', ascii(('EF', 'E'))),

            ('(?i)abcd*efg', 'ABCDEFG', '0', ascii('ABCDEFG')),
            ('(?i)ab*', 'XABYABBBZ', '0', ascii('AB')),
            ('(?i)ab*', 'XAYABBBZ', '0', ascii('A')),
            ('(?i)(ab|cd)e', 'ABCDE', '0,1', ascii(('CDE', 'CD'))),
            ('(?i)[abhgefdc]ij', 'HIJ', '0', ascii('HIJ')),
            ('(?i)^(ab|cd)e', 'ABCDE', '', ascii(None)),
            ('(?i)(abc|)ef', 'ABCDEF', '0,1', ascii(('EF', ''))),
            ('(?i)(a|b)c*d', 'ABCD', '0,1', ascii(('BCD', 'B'))),
            ('(?i)(ab|ab*)bc', 'ABC', '0,1', ascii(('ABC', 'A'))),
            ('(?i)a([bc]*)c*', 'ABC', '0,1', ascii(('ABC', 'BC'))),

            ('(?i)a([bc]*)(c*d)', 'ABCD', '0,1,2', ascii(('ABCD', 'BC', 'D'))),
            ('(?i)a([bc]+)(c*d)', 'ABCD', '0,1,2', ascii(('ABCD', 'BC', 'D'))),
            ('(?i)a([bc]*)(c+d)', 'ABCD', '0,1,2', ascii(('ABCD', 'B', 'CD'))),
            ('(?i)a[bcd]*dcdcde', 'ADCDCDE', '0', ascii('ADCDCDE')),
            ('(?i)a[bcd]+dcdcde', 'ADCDCDE', '', ascii(None)),
            ('(?i)(ab|a)b*c', 'ABC', '0,1', ascii(('ABC', 'AB'))),
            ('(?i)((a)(b)c)(d)', 'ABCD', '1,2,3,4', ascii(('ABC', 'A', 'B',
              'D'))),
            ('(?i)[a-zA-Z_][a-zA-Z0-9_]*', 'ALPHA', '0', ascii('ALPHA')),
            ('(?i)^a(bc+|b[eh])g|.h$', 'ABH', '0,1', ascii(('BH', None))),
            ('(?i)(bc+d$|ef*g.|h?i(j|k))', 'EFFGZ', '0,1,2', ascii(('EFFGZ',
              'EFFGZ', None))),

            ('(?i)(bc+d$|ef*g.|h?i(j|k))', 'IJ', '0,1,2', ascii(('IJ', 'IJ',
              'J'))),
            ('(?i)(bc+d$|ef*g.|h?i(j|k))', 'EFFG', '', ascii(None)),
            ('(?i)(bc+d$|ef*g.|h?i(j|k))', 'BCDD', '', ascii(None)),
            ('(?i)(bc+d$|ef*g.|h?i(j|k))', 'REFFGZ', '0,1,2', ascii(('EFFGZ',
              'EFFGZ', None))),
            ('(?i)((((((((((a))))))))))', 'A', '10', ascii('A')),
            ('(?i)((((((((((a))))))))))\\10', 'AA', '0', ascii('AA')),
            #('(?i)((((((((((a))))))))))\\41', 'AA', '', ascii(None)),
            #('(?i)((((((((((a))))))))))\\41', 'A!', '0', ascii('A!')),
            ('(?i)(((((((((a)))))))))', 'A', '0', ascii('A')),
            ('(?i)(?:(?:(?:(?:(?:(?:(?:(?:(?:(a))))))))))', 'A', '1',
              ascii('A')),
            ('(?i)(?:(?:(?:(?:(?:(?:(?:(?:(?:(a|b|c))))))))))', 'C', '1',
              ascii('C')),
            ('(?i)multiple words of text', 'UH-UH', '', ascii(None)),

            ('(?i)multiple words', 'MULTIPLE WORDS, YEAH', '0',
             ascii('MULTIPLE WORDS')),
            ('(?i)(.*)c(.*)', 'ABCDE', '0,1,2', ascii(('ABCDE', 'AB', 'DE'))),
            ('(?i)\\((.*), (.*)\\)', '(A, B)', '2,1', ascii(('B', 'A'))),
            ('(?i)[k]', 'AB', '', ascii(None)),
        #    ('(?i)abcd', 'ABCD', SUCCEED, 'found+"-"+\\found+"-"+\\\\found', ascii(ABCD-$&-\\ABCD)),
        #    ('(?i)a(bc)d', 'ABCD', SUCCEED, 'g1+"-"+\\g1+"-"+\\\\g1', ascii(BC-$1-\\BC)),
            ('(?i)a[-]?c', 'AC', '0', ascii('AC')),
            ('(?i)(abc)\\1', 'ABCABC', '1', ascii('ABC')),
            ('(?i)([a-c]*)\\1', 'ABCABC', '1', ascii('ABC')),
            ('a(?!b).', 'abad', '0', ascii('ad')),
            ('a(?=d).', 'abad', '0', ascii('ad')),
            ('a(?=c|d).', 'abad', '0', ascii('ad')),

            ('a(?:b|c|d)(.)', 'ace', '1', ascii('e')),
            ('a(?:b|c|d)*(.)', 'ace', '1', ascii('e')),
            ('a(?:b|c|d)+?(.)', 'ace', '1', ascii('e')),
            ('a(?:b|(c|e){1,2}?|d)+?(.)', 'ace', '1,2', ascii(('c', 'e'))),

            # Lookbehind: split by : but not if it is escaped by -.
            ('(?<!-):(.*?)(?<!-):', 'a:bc-:de:f', '1', ascii('bc-:de')),
            # Escaping with \ as we know it.
            ('(?<!\\\\):(.*?)(?<!\\\\):', 'a:bc\\:de:f', '1', ascii('bc\\:de')),
            # Terminating with ' and escaping with ? as in edifact.
            ("(?<!\\?)'(.*?)(?<!\\?)'", "a'bc?'de'f", '1', ascii("bc?'de")),

            # Comments using the (?#...) syntax.

            ('w(?# comment', 'w', '', regex.error, self.MISSING_RPAREN),
            ('w(?# comment 1)xy(?# comment 2)z', 'wxyz', '0', ascii('wxyz')),

            # Check odd placement of embedded pattern modifiers.

            # Not an error under PCRE/PRE:
            # When the new behaviour is turned on positional inline flags affect
            # only what follows.
            ('w(?i)', 'W', '0', ascii(None)),
            ('w(?i)', 'w', '0', ascii('w')),
            ('(?i)w', 'W', '0', ascii('W')),

            # Comments using the x embedded pattern modifier.
            ("""(?x)w# comment 1
x y
# comment 2
z""", 'wxyz', '0', ascii('wxyz')),

            # Using the m embedded pattern modifier.
            ('^abc', """jkl
abc
xyz""", '', ascii(None)),
            ('(?m)^abc', """jkl
abc
xyz""", '0', ascii('abc')),

            ('(?m)abc$', """jkl
xyzabc
123""", '0', ascii('abc')),

            # Using the s embedded pattern modifier.
            ('a.b', 'a\nb', '', ascii(None)),
            ('(?s)a.b', 'a\nb', '0', ascii('a\nb')),

            # Test \w, etc. both inside and outside character classes.
            ('\\w+', '--ab_cd0123--', '0', ascii('ab_cd0123')),
            ('[\\w]+', '--ab_cd0123--', '0', ascii('ab_cd0123')),
            ('\\D+', '1234abc5678', '0', ascii('abc')),
            ('[\\D]+', '1234abc5678', '0', ascii('abc')),
            ('[\\da-fA-F]+', '123abc', '0', ascii('123abc')),
            # Not an error under PCRE/PRE:
            # ('[\\d-x]', '-', '', regex.error, self.BAD_CHAR_RANGE),
            (r'([\s]*)([\S]*)([\s]*)', ' testing!1972', '3,2,1', ascii(('',
              'testing!1972', ' '))),
            (r'(\s*)(\S*)(\s*)', ' testing!1972', '3,2,1', ascii(('',
              'testing!1972', ' '))),

            #
            # Post-1.5.2 additions.

            # xmllib problem.
            (r'(([a-z]+):)?([a-z]+)$', 'smil', '1,2,3', ascii((None, None,
              'smil'))),
            # Bug 110866: reference to undefined group.
            (r'((.)\1+)', '', '', regex.error, self.OPEN_GROUP),
            # Bug 111869: search (PRE/PCRE fails on this one, SRE doesn't).
            (r'.*d', 'abc\nabd', '0', ascii('abd')),
            # Bug 112468: various expected syntax errors.
            (r'(', '', '', regex.error, self.MISSING_RPAREN),
            (r'[\41]', '!', '0', ascii('!')),
            # Bug 114033: nothing to repeat.
            (r'(x?)?', 'x', '0', ascii('x')),
            # Bug 115040: rescan if flags are modified inside pattern.
            # Changed to positional flags in regex 2023.12.23.
            (r' (?x)foo ', 'foo', '0', ascii(None)),
            (r'(?x) foo ', 'foo', '0', ascii('foo')),
            (r'(?x)foo ', 'foo', '0', ascii('foo')),
            # Bug 115618: negative lookahead.
            (r'(?<!abc)(d.f)', 'abcdefdof', '0', ascii('dof')),
            # Bug 116251: character class bug.
            (r'[\w-]+', 'laser_beam', '0', ascii('laser_beam')),
            # Bug 123769+127259: non-greedy backtracking bug.
            (r'.*?\S *:', 'xx:', '0', ascii('xx:')),
            (r'a[ ]*?\ (\d+).*', 'a   10', '0', ascii('a   10')),
            (r'a[ ]*?\ (\d+).*', 'a    10', '0', ascii('a    10')),
            # Bug 127259: \Z shouldn't depend on multiline mode.
            (r'(?ms).*?x\s*\Z(.*)','xx\nx\n', '1', ascii('')),
            # Bug 128899: uppercase literals under the ignorecase flag.
            (r'(?i)M+', 'MMM', '0', ascii('MMM')),
            (r'(?i)m+', 'MMM', '0', ascii('MMM')),
            (r'(?i)[M]+', 'MMM', '0', ascii('MMM')),
            (r'(?i)[m]+', 'MMM', '0', ascii('MMM')),
            # Bug 130748: ^* should be an error (nothing to repeat).
            # In 'regex' we won't bother to complain about this.
            # (r'^*', '', '', regex.error, self.NOTHING_TO_REPEAT),
            # Bug 133283: minimizing repeat problem.
            (r'"(?:\\"|[^"])*?"', r'"\""', '0', ascii(r'"\""')),
            # Bug 477728: minimizing repeat problem.
            (r'^.*?$', 'one\ntwo\nthree\n', '', ascii(None)),
            # Bug 483789: minimizing repeat problem.
            (r'a[^>]*?b', 'a>b', '', ascii(None)),
            # Bug 490573: minimizing repeat problem.
            (r'^a*?$', 'foo', '', ascii(None)),
            # Bug 470582: nested groups problem.
            (r'^((a)c)?(ab)$', 'ab', '1,2,3', ascii((None, None, 'ab'))),
            # Another minimizing repeat problem (capturing groups in assertions).
            ('^([ab]*?)(?=(b)?)c', 'abc', '1,2', ascii(('ab', None))),
            ('^([ab]*?)(?!(b))c', 'abc', '1,2', ascii(('ab', None))),
            ('^([ab]*?)(?<!(a))c', 'abc', '1,2', ascii(('ab', None))),
            # Bug 410271: \b broken under locales.
            (r'\b.\b', 'a', '0', ascii('a')),
            (r'\b.\b', '\N{LATIN CAPITAL LETTER A WITH DIAERESIS}', '0',
              ascii('\xc4')),
            (r'\w', '\N{LATIN CAPITAL LETTER A WITH DIAERESIS}', '0',
              ascii('\xc4')),
        ]

        for t in tests:
            excval = None
            try:
                if len(t) == 4:
                    pattern, string, groups, expected = t
                else:
                    pattern, string, groups, expected, excval = t
            except ValueError:
                fields = ", ".join([ascii(f) for f in t[ : 3]] + ["..."])
                self.fail("Incorrect number of test fields: ({})".format(fields))
            else:
                group_list = []
                if groups:
                    for group in groups.split(","):
                        try:
                            group_list.append(int(group))
                        except ValueError:
                            group_list.append(group)

                if excval is not None:
                    with self.subTest(pattern=pattern, string=string):
                        self.assertRaisesRegex(expected, excval, regex.search,
                          pattern, string)
                else:
                    m = regex.search(pattern, string)
                    if m:
                        if group_list:
                            actual = ascii(m.group(*group_list))
                        else:
                            actual = ascii(m[:])
                    else:
                        actual = ascii(m)

                    self.assertEqual(actual, expected)

    def test_replacement(self):
        self.assertEqual(regex.sub(r"test\?", "result\\?\\.\a\n", "test?"),
          "result\\?\\.\a\n")

        self.assertEqual(regex.sub('(.)', r"\1\1", 'x'), 'xx')
        self.assertEqual(regex.sub('(.)', regex.escape(r"\1\1"), 'x'), r"\1\1")
        self.assertEqual(regex.sub('(.)', r"\\1\\1", 'x'), r"\1\1")
        self.assertEqual(regex.sub('(.)', lambda m: r"\1\1", 'x'), r"\1\1")

    def test_common_prefix(self):
        # Very long common prefix
        all = string.ascii_lowercase + string.digits + string.ascii_uppercase
        side = all * 4
        regexp = '(' + side + '|' + side + ')'
        self.assertEqual(repr(type(regex.compile(regexp))), self.PATTERN_CLASS)

    def test_captures(self):
        self.assertEqual(regex.search(r"(\w)+", "abc").captures(1), ['a', 'b',
          'c'])
        self.assertEqual(regex.search(r"(\w{3})+", "abcdef").captures(0, 1),
          (['abcdef'], ['abc', 'def']))
        self.assertEqual(regex.search(r"^(\d{1,3})(?:\.(\d{1,3})){3}$",
          "192.168.0.1").captures(1, 2), (['192', ], ['168', '0', '1']))
        self.assertEqual(regex.match(r"^([0-9A-F]{2}){4} ([a-z]\d){5}$",
          "3FB52A0C a2c4g3k9d3").captures(1, 2), (['3F', 'B5', '2A', '0C'],
          ['a2', 'c4', 'g3', 'k9', 'd3']))
        self.assertEqual(regex.match("([a-z]W)([a-z]X)+([a-z]Y)",
          "aWbXcXdXeXfY").captures(1, 2, 3), (['aW'], ['bX', 'cX', 'dX', 'eX'],
          ['fY']))

        self.assertEqual(regex.search(r".*?(?=(.)+)b", "ab").captures(1),
          ['b'])
        self.assertEqual(regex.search(r".*?(?>(.){0,2})d", "abcd").captures(1),
          ['b', 'c'])
        self.assertEqual(regex.search(r"(.)+", "a").captures(1), ['a'])

    def test_guards(self):
        m = regex.search(r"(X.*?Y\s*){3}(X\s*)+AB:",
          "XY\nX Y\nX  Y\nXY\nXX AB:")
        self.assertEqual(m.span(0, 1, 2), ((3, 21), (12, 15), (16, 18)))

        m = regex.search(r"(X.*?Y\s*){3,}(X\s*)+AB:",
          "XY\nX Y\nX  Y\nXY\nXX AB:")
        self.assertEqual(m.span(0, 1, 2), ((0, 21), (12, 15), (16, 18)))

        m = regex.search(r'\d{4}(\s*\w)?\W*((?!\d)\w){2}', "9999XX")
        self.assertEqual(m.span(0, 1, 2), ((0, 6), (-1, -1), (5, 6)))

        m = regex.search(r'A\s*?.*?(\n+.*?\s*?){0,2}\(X', 'A\n1\nS\n1 (X')
        self.assertEqual(m.span(0, 1), ((0, 10), (5, 8)))

        m = regex.search(r'Derde\s*:', 'aaaaaa:\nDerde:')
        self.assertEqual(m.span(), (8, 14))
        m = regex.search(r'Derde\s*:', 'aaaaa:\nDerde:')
        self.assertEqual(m.span(), (7, 13))

    def test_turkic(self):
        # Turkish has dotted and dotless I/i.
        pairs = "I=i;I=\u0131;i=\u0130"

        all_chars = set()
        matching = set()
        for pair in pairs.split(";"):
            ch1, ch2 = pair.split("=")
            all_chars.update((ch1, ch2))
            matching.add((ch1, ch1))
            matching.add((ch1, ch2))
            matching.add((ch2, ch1))
            matching.add((ch2, ch2))

        for ch1 in all_chars:
            for ch2 in all_chars:
                m = regex.match(r"(?i)\A" + ch1 + r"\Z", ch2)
                if m:
                    if (ch1, ch2) not in matching:
                        self.fail("{} matching {}".format(ascii(ch1),
                          ascii(ch2)))
                else:
                    if (ch1, ch2) in matching:
                        self.fail("{} not matching {}".format(ascii(ch1),
                          ascii(ch2)))

    def test_named_lists(self):
        options = ["one", "two", "three"]
        self.assertEqual(regex.match(r"333\L<bar>444", "333one444",
          bar=options).group(), "333one444")
        self.assertEqual(regex.match(r"(?i)333\L<bar>444", "333TWO444",
          bar=options).group(), "333TWO444")
        self.assertEqual(regex.match(r"333\L<bar>444", "333four444",
          bar=options), None)

        options = [b"one", b"two", b"three"]
        self.assertEqual(regex.match(br"333\L<bar>444", b"333one444",
          bar=options).group(), b"333one444")
        self.assertEqual(regex.match(br"(?i)333\L<bar>444", b"333TWO444",
          bar=options).group(), b"333TWO444")
        self.assertEqual(regex.match(br"333\L<bar>444", b"333four444",
          bar=options), None)

        self.assertEqual(repr(type(regex.compile(r"3\L<bar>4\L<bar>+5",
          bar=["one", "two", "three"]))), self.PATTERN_CLASS)

        self.assertEqual(regex.findall(r"^\L<options>", "solid QWERT",
          options=set(['good', 'brilliant', '+s\\ol[i}d'])), [])
        self.assertEqual(regex.findall(r"^\L<options>", "+solid QWERT",
          options=set(['good', 'brilliant', '+solid'])), ['+solid'])

        options = ["STRASSE"]
        self.assertEqual(regex.match(r"(?fi)\L<words>",
          "stra\N{LATIN SMALL LETTER SHARP S}e", words=options).span(), (0,
          6))

        options = ["STRASSE", "stress"]
        self.assertEqual(regex.match(r"(?fi)\L<words>",
          "stra\N{LATIN SMALL LETTER SHARP S}e", words=options).span(), (0,
          6))

        options = ["stra\N{LATIN SMALL LETTER SHARP S}e"]
        self.assertEqual(regex.match(r"(?fi)\L<words>", "STRASSE",
          words=options).span(), (0, 7))

        options = ["kit"]
        self.assertEqual(regex.search(r"(?i)\L<words>", "SKITS",
          words=options).span(), (1, 4))
        self.assertEqual(regex.search(r"(?i)\L<words>",
          "SK\N{LATIN CAPITAL LETTER I WITH DOT ABOVE}TS",
          words=options).span(), (1, 4))

        self.assertEqual(regex.search(r"(?fi)\b(\w+) +\1\b",
          " stra\N{LATIN SMALL LETTER SHARP S}e STRASSE ").span(), (1, 15))
        self.assertEqual(regex.search(r"(?fi)\b(\w+) +\1\b",
          " STRASSE stra\N{LATIN SMALL LETTER SHARP S}e ").span(), (1, 15))

        self.assertEqual(regex.search(r"^\L<options>$", "", options=[]).span(),
          (0, 0))

    def test_fuzzy(self):
        # Some tests borrowed from TRE library tests.
        self.assertEqual(repr(type(regex.compile('(fou){s,e<=1}'))),
          self.PATTERN_CLASS)
        self.assertEqual(repr(type(regex.compile('(fuu){s}'))),
          self.PATTERN_CLASS)
        self.assertEqual(repr(type(regex.compile('(fuu){s,e}'))),
          self.PATTERN_CLASS)
        self.assertEqual(repr(type(regex.compile('(anaconda){1i+1d<1,s<=1}'))),
          self.PATTERN_CLASS)
        self.assertEqual(repr(type(regex.compile('(anaconda){1i+1d<1,s<=1,e<=10}'))),
          self.PATTERN_CLASS)
        self.assertEqual(repr(type(regex.compile('(anaconda){s<=1,e<=1,1i+1d<1}'))),
          self.PATTERN_CLASS)

        text = 'molasses anaconda foo bar baz smith anderson '
        self.assertEqual(regex.search('(znacnda){s<=1,e<=3,1i+1d<1}', text),
          None)
        self.assertEqual(regex.search('(znacnda){s<=1,e<=3,1i+1d<2}',
          text).span(0, 1), ((9, 17), (9, 17)))
        self.assertEqual(regex.search('(ananda){1i+1d<2}', text), None)
        self.assertEqual(regex.search(r"(?:\bznacnda){e<=2}", text)[0],
          "anaconda")
        self.assertEqual(regex.search(r"(?:\bnacnda){e<=2}", text)[0],
          "anaconda")

        text = 'anaconda foo bar baz smith anderson'
        self.assertEqual(regex.search('(fuu){i<=3,d<=3,e<=5}', text).span(0,
          1), ((0, 0), (0, 0)))
        self.assertEqual(regex.search('(?b)(fuu){i<=3,d<=3,e<=5}',
          text).span(0, 1), ((9, 10), (9, 10)))
        self.assertEqual(regex.search('(fuu){i<=2,d<=2,e<=5}', text).span(0,
          1), ((7, 10), (7, 10)))
        self.assertEqual(regex.search('(?e)(fuu){i<=2,d<=2,e<=5}',
          text).span(0, 1), ((9, 10), (9, 10)))
        self.assertEqual(regex.search('(fuu){i<=3,d<=3,e}', text).span(0, 1),
          ((0, 0), (0, 0)))
        self.assertEqual(regex.search('(?b)(fuu){i<=3,d<=3,e}', text).span(0,
          1), ((9, 10), (9, 10)))

        self.assertEqual(repr(type(regex.compile('(approximate){s<=3,1i+1d<3}'))),
          self.PATTERN_CLASS)

        # No cost limit.
        self.assertEqual(regex.search('(foobar){e}',
          'xirefoabralfobarxie').span(0, 1), ((0, 6), (0, 6)))
        self.assertEqual(regex.search('(?e)(foobar){e}',
          'xirefoabralfobarxie').span(0, 1), ((0, 3), (0, 3)))
        self.assertEqual(regex.search('(?b)(foobar){e}',
          'xirefoabralfobarxie').span(0, 1), ((11, 16), (11, 16)))

        # At most two errors.
        self.assertEqual(regex.search('(foobar){e<=2}',
          'xirefoabrzlfd').span(0, 1), ((4, 9), (4, 9)))
        self.assertEqual(regex.search('(foobar){e<=2}', 'xirefoabzlfd'), None)

        # At most two inserts or substitutions and max two errors total.
        self.assertEqual(regex.search('(foobar){i<=2,s<=2,e<=2}',
          'oobargoobaploowap').span(0, 1), ((5, 11), (5, 11)))

        # Find best whole word match for "foobar".
        self.assertEqual(regex.search('\\b(foobar){e}\\b', 'zfoobarz').span(0,
          1), ((0, 8), (0, 8)))
        self.assertEqual(regex.search('\\b(foobar){e}\\b',
          'boing zfoobarz goobar woop').span(0, 1), ((0, 6), (0, 6)))
        self.assertEqual(regex.search('(?b)\\b(foobar){e}\\b',
          'boing zfoobarz goobar woop').span(0, 1), ((15, 21), (15, 21)))

        # Match whole string, allow only 1 error.
        self.assertEqual(regex.search('^(foobar){e<=1}$', 'foobar').span(0, 1),
          ((0, 6), (0, 6)))
        self.assertEqual(regex.search('^(foobar){e<=1}$', 'xfoobar').span(0,
          1), ((0, 7), (0, 7)))
        self.assertEqual(regex.search('^(foobar){e<=1}$', 'foobarx').span(0,
          1), ((0, 7), (0, 7)))
        self.assertEqual(regex.search('^(foobar){e<=1}$', 'fooxbar').span(0,
          1), ((0, 7), (0, 7)))
        self.assertEqual(regex.search('^(foobar){e<=1}$', 'foxbar').span(0, 1),
          ((0, 6), (0, 6)))
        self.assertEqual(regex.search('^(foobar){e<=1}$', 'xoobar').span(0, 1),
          ((0, 6), (0, 6)))
        self.assertEqual(regex.search('^(foobar){e<=1}$', 'foobax').span(0, 1),
          ((0, 6), (0, 6)))
        self.assertEqual(regex.search('^(foobar){e<=1}$', 'oobar').span(0, 1),
          ((0, 5), (0, 5)))
        self.assertEqual(regex.search('^(foobar){e<=1}$', 'fobar').span(0, 1),
          ((0, 5), (0, 5)))
        self.assertEqual(regex.search('^(foobar){e<=1}$', 'fooba').span(0, 1),
          ((0, 5), (0, 5)))
        self.assertEqual(regex.search('^(foobar){e<=1}$', 'xfoobarx'), None)
        self.assertEqual(regex.search('^(foobar){e<=1}$', 'foobarxx'), None)
        self.assertEqual(regex.search('^(foobar){e<=1}$', 'xxfoobar'), None)
        self.assertEqual(regex.search('^(foobar){e<=1}$', 'xfoxbar'), None)
        self.assertEqual(regex.search('^(foobar){e<=1}$', 'foxbarx'), None)

        # At most one insert, two deletes, and three substitutions.
        # Additionally, deletes cost two and substitutes one, and total
        # cost must be less than 4.
        self.assertEqual(regex.search('(foobar){i<=1,d<=2,s<=3,2d+1s<4}',
          '3oifaowefbaoraofuiebofasebfaobfaorfeoaro').span(0, 1), ((6, 13), (6,
          13)))
        self.assertEqual(regex.search('(?b)(foobar){i<=1,d<=2,s<=3,2d+1s<4}',
          '3oifaowefbaoraofuiebofasebfaobfaorfeoaro').span(0, 1), ((34, 39),
          (34, 39)))

        # Partially fuzzy matches.
        self.assertEqual(regex.search('foo(bar){e<=1}zap', 'foobarzap').span(0,
          1), ((0, 9), (3, 6)))
        self.assertEqual(regex.search('foo(bar){e<=1}zap', 'fobarzap'), None)
        self.assertEqual(regex.search('foo(bar){e<=1}zap', 'foobrzap').span(0,
          1), ((0, 8), (3, 5)))

        text = ('www.cnn.com 64.236.16.20\nwww.slashdot.org 66.35.250.150\n'
          'For useful information, use www.slashdot.org\nthis is demo data!\n')
        self.assertEqual(regex.search(r'(?s)^.*(dot.org){e}.*$', text).span(0,
          1), ((0, 120), (120, 120)))
        self.assertEqual(regex.search(r'(?es)^.*(dot.org){e}.*$', text).span(0,
          1), ((0, 120), (93, 100)))
        self.assertEqual(regex.search(r'^.*(dot.org){e}.*$', text).span(0, 1),
          ((0, 119), (24, 101)))

        # Behaviour is unexpected, but arguably not wrong. It first finds the
        # best match, then the best in what follows, etc.
        self.assertEqual(regex.findall(r"\b\L<words>{e<=1}\b",
          " book cot dog desk ", words="cat dog".split()), ["cot", "dog"])
        self.assertEqual(regex.findall(r"\b\L<words>{e<=1}\b",
          " book dog cot desk ", words="cat dog".split()), [" dog", "cot"])
        self.assertEqual(regex.findall(r"(?e)\b\L<words>{e<=1}\b",
          " book dog cot desk ", words="cat dog".split()), ["dog", "cot"])
        self.assertEqual(regex.findall(r"(?r)\b\L<words>{e<=1}\b",
          " book cot dog desk ", words="cat dog".split()), ["dog ", "cot"])
        self.assertEqual(regex.findall(r"(?er)\b\L<words>{e<=1}\b",
          " book cot dog desk ", words="cat dog".split()), ["dog", "cot"])
        self.assertEqual(regex.findall(r"(?r)\b\L<words>{e<=1}\b",
          " book dog cot desk ", words="cat dog".split()), ["cot", "dog"])
        self.assertEqual(regex.findall(br"\b\L<words>{e<=1}\b",
          b" book cot dog desk ", words=b"cat dog".split()), [b"cot", b"dog"])
        self.assertEqual(regex.findall(br"\b\L<words>{e<=1}\b",
          b" book dog cot desk ", words=b"cat dog".split()), [b" dog", b"cot"])
        self.assertEqual(regex.findall(br"(?e)\b\L<words>{e<=1}\b",
          b" book dog cot desk ", words=b"cat dog".split()), [b"dog", b"cot"])
        self.assertEqual(regex.findall(br"(?r)\b\L<words>{e<=1}\b",
          b" book cot dog desk ", words=b"cat dog".split()), [b"dog ", b"cot"])
        self.assertEqual(regex.findall(br"(?er)\b\L<words>{e<=1}\b",
          b" book cot dog desk ", words=b"cat dog".split()), [b"dog", b"cot"])
        self.assertEqual(regex.findall(br"(?r)\b\L<words>{e<=1}\b",
          b" book dog cot desk ", words=b"cat dog".split()), [b"cot", b"dog"])

        self.assertEqual(regex.search(r"(\w+) (\1{e<=1})", "foo fou").groups(),
          ("foo", "fou"))
        self.assertEqual(regex.search(r"(?r)(\2{e<=1}) (\w+)",
          "foo fou").groups(), ("foo", "fou"))
        self.assertEqual(regex.search(br"(\w+) (\1{e<=1})",
          b"foo fou").groups(), (b"foo", b"fou"))

        self.assertEqual(regex.findall(r"(?:(?:QR)+){e}", "abcde"), ["abcde",
          ""])
        self.assertEqual(regex.findall(r"(?:Q+){e}", "abc"), ["abc", ""])

        # Hg issue 41: = for fuzzy matches
        self.assertEqual(regex.match(r"(?:service detection){0<e<5}",
          "servic detection").span(), (0, 16))
        self.assertEqual(regex.match(r"(?:service detection){0<e<5}",
          "service detect").span(), (0, 14))
        self.assertEqual(regex.match(r"(?:service detection){0<e<5}",
          "service detecti").span(), (0, 15))
        self.assertEqual(regex.match(r"(?:service detection){0<e<5}",
          "service detection"), None)
        self.assertEqual(regex.match(r"(?:service detection){0<e<5}",
          "in service detection").span(), (0, 20))

        # Hg issue 109: Edit distance of fuzzy match
        self.assertEqual(regex.fullmatch(r"(?:cats|cat){e<=1}",
          "cat").fuzzy_counts, (0, 0, 1))
        self.assertEqual(regex.fullmatch(r"(?e)(?:cats|cat){e<=1}",
          "cat").fuzzy_counts, (0, 0, 0))

        self.assertEqual(regex.fullmatch(r"(?:cat|cats){e<=1}",
          "cats").fuzzy_counts, (0, 1, 0))
        self.assertEqual(regex.fullmatch(r"(?e)(?:cat|cats){e<=1}",
          "cats").fuzzy_counts, (0, 0, 0))

        self.assertEqual(regex.fullmatch(r"(?:cat){e<=1} (?:cat){e<=1}",
          "cat cot").fuzzy_counts, (1, 0, 0))

        # Incorrect fuzzy changes
        self.assertEqual(regex.search(r"(?e)(GTTTTCATTCCTCATA){i<=4,d<=4,s<=4,i+d+s<=8}",
          "ATTATTTATTTTTCATA").fuzzy_changes, ([0, 6, 10, 11], [3], []))

        # Fuzzy constraints ignored when checking for prefix/suffix in branches
        self.assertEqual(bool(regex.match('(?:fo){e<=1}|(?:fo){e<=2}', 'FO')),
          True)

    def test_recursive(self):
        self.assertEqual(regex.search(r"(\w)(?:(?R)|(\w?))\1", "xx")[ : ],
          ("xx", "x", ""))
        self.assertEqual(regex.search(r"(\w)(?:(?R)|(\w?))\1", "aba")[ : ],
          ("aba", "a", "b"))
        self.assertEqual(regex.search(r"(\w)(?:(?R)|(\w?))\1", "abba")[ : ],
          ("abba", "a", None))
        self.assertEqual(regex.search(r"(\w)(?:(?R)|(\w?))\1", "kayak")[ : ],
          ("kayak", "k", None))
        self.assertEqual(regex.search(r"(\w)(?:(?R)|(\w?))\1", "paper")[ : ],
          ("pap", "p", "a"))
        self.assertEqual(regex.search(r"(\w)(?:(?R)|(\w?))\1", "dontmatchme"),
          None)

        self.assertEqual(regex.search(r"(?r)\2(?:(\w?)|(?R))(\w)", "xx")[ : ],
          ("xx", "", "x"))
        self.assertEqual(regex.search(r"(?r)\2(?:(\w?)|(?R))(\w)", "aba")[ : ],
          ("aba", "b", "a"))
        self.assertEqual(regex.search(r"(?r)\2(?:(\w?)|(?R))(\w)", "abba")[ :
          ], ("abba", None, "a"))
        self.assertEqual(regex.search(r"(?r)\2(?:(\w?)|(?R))(\w)", "kayak")[ :
          ], ("kayak", None, "k"))
        self.assertEqual(regex.search(r"(?r)\2(?:(\w?)|(?R))(\w)", "paper")[ :
          ], ("pap", "a", "p"))
        self.assertEqual(regex.search(r"(?r)\2(?:(\w?)|(?R))(\w)",
          "dontmatchme"), None)

        self.assertEqual(regex.search(r"\(((?>[^()]+)|(?R))*\)", "(ab(cd)ef)")[
          : ], ("(ab(cd)ef)", "ef"))
        self.assertEqual(regex.search(r"\(((?>[^()]+)|(?R))*\)",
          "(ab(cd)ef)").captures(1), ["ab", "cd", "(cd)", "ef"])

        self.assertEqual(regex.search(r"(?r)\(((?R)|(?>[^()]+))*\)",
          "(ab(cd)ef)")[ : ], ("(ab(cd)ef)", "ab"))
        self.assertEqual(regex.search(r"(?r)\(((?R)|(?>[^()]+))*\)",
          "(ab(cd)ef)").captures(1), ["ef", "cd", "(cd)", "ab"])

        self.assertEqual(regex.search(r"\(([^()]+|(?R))*\)",
          "some text (a(b(c)d)e) more text")[ : ], ("(a(b(c)d)e)", "e"))

        self.assertEqual(regex.search(r"(?r)\(((?R)|[^()]+)*\)",
          "some text (a(b(c)d)e) more text")[ : ], ("(a(b(c)d)e)", "a"))

        self.assertEqual(regex.search(r"(foo(\(((?:(?>[^()]+)|(?2))*)\)))",
          "foo(bar(baz)+baz(bop))")[ : ], ("foo(bar(baz)+baz(bop))",
          "foo(bar(baz)+baz(bop))", "(bar(baz)+baz(bop))",
          "bar(baz)+baz(bop)"))

        self.assertEqual(regex.search(r"(?r)(foo(\(((?:(?2)|(?>[^()]+))*)\)))",
          "foo(bar(baz)+baz(bop))")[ : ], ("foo(bar(baz)+baz(bop))",
          "foo(bar(baz)+baz(bop))", "(bar(baz)+baz(bop))",
          "bar(baz)+baz(bop)"))

        rgx = regex.compile(r"""^\s*(<\s*([a-zA-Z:]+)(?:\s*[a-zA-Z:]*\s*=\s*(?:'[^']*'|"[^"]*"))*\s*(/\s*)?>(?:[^<>]*|(?1))*(?(3)|<\s*/\s*\2\s*>))\s*$""")
        self.assertEqual(bool(rgx.search('<foo><bar></bar></foo>')), True)
        self.assertEqual(bool(rgx.search('<foo><bar></foo></bar>')), False)
        self.assertEqual(bool(rgx.search('<foo><bar/></foo>')), True)
        self.assertEqual(bool(rgx.search('<foo><bar></foo>')), False)
        self.assertEqual(bool(rgx.search('<foo bar=baz/>')), False)

        self.assertEqual(bool(rgx.search('<foo bar="baz">')), False)
        self.assertEqual(bool(rgx.search('<foo bar="baz"/>')), True)
        self.assertEqual(bool(rgx.search('<    fooo   /  >')), True)
        # The next regex should and does match. Perl 5.14 agrees.
        #self.assertEqual(bool(rgx.search('<foo/>foo')), False)
        self.assertEqual(bool(rgx.search('foo<foo/>')), False)

        self.assertEqual(bool(rgx.search('<foo>foo</foo>')), True)
        self.assertEqual(bool(rgx.search('<foo><bar/>foo</foo>')), True)
        self.assertEqual(bool(rgx.search('<a><b><c></c></b></a>')), True)

    def test_copy(self):
        # PatternObjects are immutable, therefore there's no need to clone them.
        r = regex.compile("a")
        self.assertTrue(copy.copy(r) is r)
        self.assertTrue(copy.deepcopy(r) is r)

        # MatchObjects are normally mutable because the target string can be
        # detached. However, after the target string has been detached, a
        # MatchObject becomes immutable, so there's no need to clone it.
        m = r.match("a")
        self.assertTrue(copy.copy(m) is not m)
        self.assertTrue(copy.deepcopy(m) is not m)

        self.assertTrue(m.string is not None)
        m2 = copy.copy(m)
        m2.detach_string()
        self.assertTrue(m.string is not None)
        self.assertTrue(m2.string is None)

        # The following behaviour matches that of the re module.
        it = regex.finditer(".", "ab")
        it2 = copy.copy(it)
        self.assertEqual(next(it).group(), "a")
        self.assertEqual(next(it2).group(), "b")

        # The following behaviour matches that of the re module.
        it = regex.finditer(".", "ab")
        it2 = copy.deepcopy(it)
        self.assertEqual(next(it).group(), "a")
        self.assertEqual(next(it2).group(), "b")

        # The following behaviour is designed to match that of copying 'finditer'.
        it = regex.splititer(" ", "a b")
        it2 = copy.copy(it)
        self.assertEqual(next(it), "a")
        self.assertEqual(next(it2), "b")

        # The following behaviour is designed to match that of copying 'finditer'.
        it = regex.splititer(" ", "a b")
        it2 = copy.deepcopy(it)
        self.assertEqual(next(it), "a")
        self.assertEqual(next(it2), "b")

    def test_format(self):
        self.assertEqual(regex.subf(r"(\w+) (\w+)", "{0} => {2} {1}",
          "foo bar"), "foo bar => bar foo")
        self.assertEqual(regex.subf(r"(?<word1>\w+) (?<word2>\w+)",
          "{word2} {word1}", "foo bar"), "bar foo")

        self.assertEqual(regex.subfn(r"(\w+) (\w+)", "{0} => {2} {1}",
          "foo bar"), ("foo bar => bar foo", 1))
        self.assertEqual(regex.subfn(r"(?<word1>\w+) (?<word2>\w+)",
          "{word2} {word1}", "foo bar"), ("bar foo", 1))

        self.assertEqual(regex.match(r"(\w+) (\w+)",
          "foo bar").expandf("{0} => {2} {1}"), "foo bar => bar foo")

    def test_fullmatch(self):
        self.assertEqual(bool(regex.fullmatch(r"abc", "abc")), True)
        self.assertEqual(bool(regex.fullmatch(r"abc", "abcx")), False)
        self.assertEqual(bool(regex.fullmatch(r"abc", "abcx", endpos=3)), True)

        self.assertEqual(bool(regex.fullmatch(r"abc", "xabc", pos=1)), True)
        self.assertEqual(bool(regex.fullmatch(r"abc", "xabcy", pos=1)), False)
        self.assertEqual(bool(regex.fullmatch(r"abc", "xabcy", pos=1,
          endpos=4)), True)

        self.assertEqual(bool(regex.fullmatch(r"(?r)abc", "abc")), True)
        self.assertEqual(bool(regex.fullmatch(r"(?r)abc", "abcx")), False)
        self.assertEqual(bool(regex.fullmatch(r"(?r)abc", "abcx", endpos=3)),
          True)

        self.assertEqual(bool(regex.fullmatch(r"(?r)abc", "xabc", pos=1)),
          True)
        self.assertEqual(bool(regex.fullmatch(r"(?r)abc", "xabcy", pos=1)),
          False)
        self.assertEqual(bool(regex.fullmatch(r"(?r)abc", "xabcy", pos=1,
          endpos=4)), True)

    def test_issue_18468(self):
        self.assertTypedEqual(regex.sub('y', 'a', 'xyz'), 'xaz')
        self.assertTypedEqual(regex.sub('y', StrSubclass('a'),
          StrSubclass('xyz')), 'xaz')
        self.assertTypedEqual(regex.sub(b'y', b'a', b'xyz'), b'xaz')
        self.assertTypedEqual(regex.sub(b'y', BytesSubclass(b'a'),
          BytesSubclass(b'xyz')), b'xaz')
        self.assertTypedEqual(regex.sub(b'y', bytearray(b'a'),
          bytearray(b'xyz')), b'xaz')
        self.assertTypedEqual(regex.sub(b'y', memoryview(b'a'),
          memoryview(b'xyz')), b'xaz')

        for string in ":a:b::c", StrSubclass(":a:b::c"):
            self.assertTypedEqual(regex.split(":", string), ['', 'a', 'b', '',
              'c'])
            if sys.version_info >= (3, 7, 0):
                self.assertTypedEqual(regex.split(":*", string), ['', '', 'a',
                  '', 'b', '', 'c', ''])
                self.assertTypedEqual(regex.split("(:*)", string), ['', ':',
                  '', '', 'a', ':', '', '', 'b', '::', '', '', 'c', '', ''])
            else:
                self.assertTypedEqual(regex.split(":*", string), ['', 'a', 'b',
                  'c'])
                self.assertTypedEqual(regex.split("(:*)", string), ['', ':',
                  'a', ':', 'b', '::', 'c'])

        for string in (b":a:b::c", BytesSubclass(b":a:b::c"),
          bytearray(b":a:b::c"), memoryview(b":a:b::c")):
            self.assertTypedEqual(regex.split(b":", string), [b'', b'a', b'b',
              b'', b'c'])
            if sys.version_info >= (3, 7, 0):
                self.assertTypedEqual(regex.split(b":*", string), [b'', b'',
                  b'a', b'', b'b', b'', b'c', b''])
                self.assertTypedEqual(regex.split(b"(:*)", string), [b'', b':',
                  b'', b'', b'a', b':', b'', b'', b'b', b'::', b'', b'', b'c',
                  b'', b''])
            else:
                self.assertTypedEqual(regex.split(b":*", string), [b'', b'a',
                  b'b', b'c'])
                self.assertTypedEqual(regex.split(b"(:*)", string), [b'', b':',
                  b'a', b':', b'b', b'::', b'c'])

        for string in "a:b::c:::d", StrSubclass("a:b::c:::d"):
            self.assertTypedEqual(regex.findall(":+", string), [":", "::",
              ":::"])
            self.assertTypedEqual(regex.findall("(:+)", string), [":", "::",
              ":::"])
            self.assertTypedEqual(regex.findall("(:)(:*)", string), [(":", ""),
              (":", ":"), (":", "::")])

        for string in (b"a:b::c:::d", BytesSubclass(b"a:b::c:::d"),
          bytearray(b"a:b::c:::d"), memoryview(b"a:b::c:::d")):
            self.assertTypedEqual(regex.findall(b":+", string), [b":", b"::",
              b":::"])
            self.assertTypedEqual(regex.findall(b"(:+)", string), [b":", b"::",
              b":::"])
            self.assertTypedEqual(regex.findall(b"(:)(:*)", string), [(b":",
              b""), (b":", b":"), (b":", b"::")])

        for string in 'a', StrSubclass('a'):
            self.assertEqual(regex.match('a', string).groups(), ())
            self.assertEqual(regex.match('(a)', string).groups(), ('a',))
            self.assertEqual(regex.match('(a)', string).group(0), 'a')
            self.assertEqual(regex.match('(a)', string).group(1), 'a')
            self.assertEqual(regex.match('(a)', string).group(1, 1), ('a',
              'a'))

        for string in (b'a', BytesSubclass(b'a'), bytearray(b'a'),
          memoryview(b'a')):
            self.assertEqual(regex.match(b'a', string).groups(), ())
            self.assertEqual(regex.match(b'(a)', string).groups(), (b'a',))
            self.assertEqual(regex.match(b'(a)', string).group(0), b'a')
            self.assertEqual(regex.match(b'(a)', string).group(1), b'a')
            self.assertEqual(regex.match(b'(a)', string).group(1, 1), (b'a',
              b'a'))

    def test_partial(self):
        self.assertEqual(regex.match('ab', 'a', partial=True).partial, True)
        self.assertEqual(regex.match('ab', 'a', partial=True).span(), (0, 1))
        self.assertEqual(regex.match(r'cats', 'cat', partial=True).partial,
          True)
        self.assertEqual(regex.match(r'cats', 'cat', partial=True).span(), (0,
          3))
        self.assertEqual(regex.match(r'cats', 'catch', partial=True), None)
        self.assertEqual(regex.match(r'abc\w{3}', 'abcdef',
          partial=True).partial, False)
        self.assertEqual(regex.match(r'abc\w{3}', 'abcdef',
          partial=True).span(), (0, 6))
        self.assertEqual(regex.match(r'abc\w{3}', 'abcde',
          partial=True).partial, True)
        self.assertEqual(regex.match(r'abc\w{3}', 'abcde',
          partial=True).span(), (0, 5))

        self.assertEqual(regex.match(r'\d{4}$', '1234', partial=True).partial,
          False)

        self.assertEqual(regex.match(r'\L<words>', 'post', partial=True,
          words=['post']).partial, False)
        self.assertEqual(regex.match(r'\L<words>', 'post', partial=True,
          words=['post']).span(), (0, 4))
        self.assertEqual(regex.match(r'\L<words>', 'pos', partial=True,
          words=['post']).partial, True)
        self.assertEqual(regex.match(r'\L<words>', 'pos', partial=True,
          words=['post']).span(), (0, 3))

        self.assertEqual(regex.match(r'(?fi)\L<words>', 'POST', partial=True,
          words=['po\uFB06']).partial, False)
        self.assertEqual(regex.match(r'(?fi)\L<words>', 'POST', partial=True,
          words=['po\uFB06']).span(), (0, 4))
        self.assertEqual(regex.match(r'(?fi)\L<words>', 'POS', partial=True,
          words=['po\uFB06']).partial, True)
        self.assertEqual(regex.match(r'(?fi)\L<words>', 'POS', partial=True,
          words=['po\uFB06']).span(), (0, 3))
        self.assertEqual(regex.match(r'(?fi)\L<words>', 'po\uFB06',
          partial=True, words=['POS']), None)

        self.assertEqual(regex.match(r'[a-z]*4R$', 'a', partial=True).span(),
          (0, 1))
        self.assertEqual(regex.match(r'[a-z]*4R$', 'ab', partial=True).span(),
          (0, 2))
        self.assertEqual(regex.match(r'[a-z]*4R$', 'ab4', partial=True).span(),
          (0, 3))
        self.assertEqual(regex.match(r'[a-z]*4R$', 'a4', partial=True).span(),
          (0, 2))
        self.assertEqual(regex.match(r'[a-z]*4R$', 'a4R', partial=True).span(),
          (0, 3))
        self.assertEqual(regex.match(r'[a-z]*4R$', '4a', partial=True), None)
        self.assertEqual(regex.match(r'[a-z]*4R$', 'a44', partial=True), None)

    def test_hg_bugs(self):
        # Hg issue 28: regex.compile("(?>b)") causes "TypeError: 'Character'
        # object is not subscriptable"
        self.assertEqual(bool(regex.compile("(?>b)", flags=regex.V1)), True)

        # Hg issue 29: regex.compile("^((?>\w+)|(?>\s+))*$") causes
        # "TypeError: 'GreedyRepeat' object is not iterable"
        self.assertEqual(bool(regex.compile(r"^((?>\w+)|(?>\s+))*$",
          flags=regex.V1)), True)

        # Hg issue 31: atomic and normal groups in recursive patterns
        self.assertEqual(regex.findall(r"\((?:(?>[^()]+)|(?R))*\)",
          "a(bcd(e)f)g(h)"), ['(bcd(e)f)', '(h)'])
        self.assertEqual(regex.findall(r"\((?:(?:[^()]+)|(?R))*\)",
          "a(bcd(e)f)g(h)"), ['(bcd(e)f)', '(h)'])
        self.assertEqual(regex.findall(r"\((?:(?>[^()]+)|(?R))*\)",
          "a(b(cd)e)f)g)h"), ['(b(cd)e)'])
        self.assertEqual(regex.findall(r"\((?:(?>[^()]+)|(?R))*\)",
          "a(bc(d(e)f)gh"), ['(d(e)f)'])
        self.assertEqual(regex.findall(r"(?r)\((?:(?>[^()]+)|(?R))*\)",
          "a(bc(d(e)f)gh"), ['(d(e)f)'])
        self.assertEqual([m.group() for m in
          regex.finditer(r"\((?:[^()]*+|(?0))*\)", "a(b(c(de)fg)h")],
          ['(c(de)fg)'])

        # Hg issue 32: regex.search("a(bc)d", "abcd", regex.I|regex.V1) returns
        # None
        self.assertEqual(regex.search("a(bc)d", "abcd", regex.I |
          regex.V1).group(0), "abcd")

        # Hg issue 33: regex.search("([\da-f:]+)$", "E", regex.I|regex.V1)
        # returns None
        self.assertEqual(regex.search(r"([\da-f:]+)$", "E", regex.I |
          regex.V1).group(0), "E")
        self.assertEqual(regex.search(r"([\da-f:]+)$", "e", regex.I |
          regex.V1).group(0), "e")

        # Hg issue 34: regex.search("^(?=ab(de))(abd)(e)", "abde").groups()
        # returns (None, 'abd', 'e') instead of ('de', 'abd', 'e')
        self.assertEqual(regex.search("^(?=ab(de))(abd)(e)", "abde").groups(),
          ('de', 'abd', 'e'))

        # Hg issue 35: regex.compile("\ ", regex.X) causes "_regex_core.error:
        # bad escape"
        self.assertEqual(bool(regex.match(r"\ ", " ", flags=regex.X)), True)

        # Hg issue 36: regex.search("^(a|)\1{2}b", "b") returns None
        self.assertEqual(regex.search(r"^(a|)\1{2}b", "b").group(0, 1), ('b',
          ''))

        # Hg issue 37: regex.search("^(a){0,0}", "abc").group(0,1) returns
        # ('a', 'a') instead of ('', None)
        self.assertEqual(regex.search("^(a){0,0}", "abc").group(0, 1), ('',
          None))

        # Hg issue 38: regex.search("(?>.*/)b", "a/b") returns None
        self.assertEqual(regex.search("(?>.*/)b", "a/b").group(0), "a/b")

        # Hg issue 39: regex.search("((?i)blah)\\s+\\1", "blah BLAH") doesn't
        # return None
        # Changed to positional flags in regex 2023.12.23.
        self.assertEqual(regex.search(r"((?i)blah)\s+\1", "blah BLAH"), None)

        # Hg issue 40: regex.search("(\()?[^()]+(?(1)\)|)", "(abcd").group(0)
        # returns "bcd" instead of "abcd"
        self.assertEqual(regex.search(r"(\()?[^()]+(?(1)\)|)",
          "(abcd").group(0), "abcd")

        # Hg issue 42: regex.search("(a*)*", "a", flags=regex.V1).span(1)
        # returns (0, 1) instead of (1, 1)
        self.assertEqual(regex.search("(a*)*", "a").span(1), (1, 1))
        self.assertEqual(regex.search("(a*)*", "aa").span(1), (2, 2))
        self.assertEqual(regex.search("(a*)*", "aaa").span(1), (3, 3))

        # Hg issue 43: regex.compile("a(?#xxx)*") causes "_regex_core.error:
        # nothing to repeat"
        self.assertEqual(regex.search("a(?#xxx)*", "aaa").group(), "aaa")

        # Hg issue 44: regex.compile("(?=abc){3}abc") causes
        # "_regex_core.error: nothing to repeat"
        self.assertEqual(regex.search("(?=abc){3}abc", "abcabcabc").span(), (0,
          3))

        # Hg issue 45: regex.compile("^(?:a(?:(?:))+)+") causes
        # "_regex_core.error: nothing to repeat"
        self.assertEqual(regex.search("^(?:a(?:(?:))+)+", "a").span(), (0, 1))
        self.assertEqual(regex.search("^(?:a(?:(?:))+)+", "aa").span(), (0, 2))

        # Hg issue 46: regex.compile("a(?x: b c )d") causes
        # "_regex_core.error: missing )"
        self.assertEqual(regex.search("a(?x: b c )d", "abcd").group(0), "abcd")

        # Hg issue 47: regex.compile("a#comment\n*", flags=regex.X) causes
        # "_regex_core.error: nothing to repeat"
        self.assertEqual(regex.search("a#comment\n*", "aaa",
          flags=regex.X).group(0), "aaa")

        # Hg issue 48: regex.search("(a(?(1)\\1)){4}", "a"*10,
        # flags=regex.V1).group(0,1) returns ('aaaaa', 'a') instead of ('aaaaaaaaaa', 'aaaa')
        self.assertEqual(regex.search(r"(?V1)(a(?(1)\1)){1}",
          "aaaaaaaaaa").span(0, 1), ((0, 1), (0, 1)))
        self.assertEqual(regex.search(r"(?V1)(a(?(1)\1)){2}",
          "aaaaaaaaaa").span(0, 1), ((0, 3), (1, 3)))
        self.assertEqual(regex.search(r"(?V1)(a(?(1)\1)){3}",
          "aaaaaaaaaa").span(0, 1), ((0, 6), (3, 6)))
        self.assertEqual(regex.search(r"(?V1)(a(?(1)\1)){4}",
          "aaaaaaaaaa").span(0, 1), ((0, 10), (6, 10)))

        # Hg issue 49: regex.search("(a)(?<=b(?1))", "baz", regex.V1) returns
        # None incorrectly
        self.assertEqual(regex.search("(?V1)(a)(?<=b(?1))", "baz").group(0),
          "a")

        # Hg issue 50: not all keywords are found by named list with
        # overlapping keywords when full Unicode casefolding is required
        self.assertEqual(regex.findall(r'(?fi)\L<keywords>',
          'POST, Post, post, po\u017Ft, po\uFB06, and po\uFB05',
          keywords=['post','pos']), ['POST', 'Post', 'post', 'po\u017Ft',
          'po\uFB06', 'po\uFB05'])
        self.assertEqual(regex.findall(r'(?fi)pos|post',
          'POST, Post, post, po\u017Ft, po\uFB06, and po\uFB05'), ['POS',
          'Pos', 'pos', 'po\u017F', 'po\uFB06', 'po\uFB05'])
        self.assertEqual(regex.findall(r'(?fi)post|pos',
          'POST, Post, post, po\u017Ft, po\uFB06, and po\uFB05'), ['POST',
          'Post', 'post', 'po\u017Ft', 'po\uFB06', 'po\uFB05'])
        self.assertEqual(regex.findall(r'(?fi)post|another',
          'POST, Post, post, po\u017Ft, po\uFB06, and po\uFB05'), ['POST',
          'Post', 'post', 'po\u017Ft', 'po\uFB06', 'po\uFB05'])

        # Hg issue 51: regex.search("((a)(?1)|(?2))", "a", flags=regex.V1)
        # returns None incorrectly
        self.assertEqual(regex.search("(?V1)((a)(?1)|(?2))", "a").group(0, 1,
          2), ('a', 'a', None))

        # Hg issue 52: regex.search("(\\1xx|){6}", "xx",
        # flags=regex.V1).span(0,1) returns incorrect value
        self.assertEqual(regex.search(r"(?V1)(\1xx|){6}", "xx").span(0, 1),
          ((0, 2), (2, 2)))

        # Hg issue 53: regex.search("(a|)+", "a") causes MemoryError
        self.assertEqual(regex.search("(a|)+", "a").group(0, 1), ("a", ""))

        # Hg issue 54: regex.search("(a|)*\\d", "a"*80) causes MemoryError
        self.assertEqual(regex.search(r"(a|)*\d", "a" * 80), None)

        # Hg issue 55: regex.search("^(?:a?b?)*$", "ac") take a very long time.
        self.assertEqual(regex.search("^(?:a?b?)*$", "ac"), None)

        # Hg issue 58: bad named character escape sequences like "\\N{1}"
        # treats as "N"
        self.assertRaisesRegex(regex.error, self.UNDEF_CHAR_NAME, lambda:
          regex.compile("\\N{1}"))

        # Hg issue 59: regex.search("\\Z", "a\na\n") returns None incorrectly
        self.assertEqual(regex.search("\\Z", "a\na\n").span(0), (4, 4))

        # Hg issue 60: regex.search("(q1|.)*(q2|.)*(x(a|bc)*y){2,}", "xayxay")
        # returns None incorrectly
        self.assertEqual(regex.search("(q1|.)*(q2|.)*(x(a|bc)*y){2,}",
          "xayxay").group(0), "xayxay")

        # Hg issue 61: regex.search("[^a]", "A", regex.I).group(0) returns ''
        # incorrectly
        self.assertEqual(regex.search("(?i)[^a]", "A"), None)

        # Hg issue 63: regex.search("[[:ascii:]]", "\N{KELVIN SIGN}",
        # flags=regex.I|regex.V1) doesn't return None
        self.assertEqual(regex.search("(?i)[[:ascii:]]", "\N{KELVIN SIGN}"),
          None)

        # Hg issue 66: regex.search("((a|b(?1)c){3,5})", "baaaaca",
        # flags=regex.V1).groups() returns ('baaaac', 'baaaac') instead of ('aaaa', 'a')
        self.assertEqual(regex.search("((a|b(?1)c){3,5})", "baaaaca").group(0,
          1, 2), ('aaaa', 'aaaa', 'a'))

        # Hg issue 71: non-greedy quantifier in lookbehind
        self.assertEqual(regex.findall(r"(?<=:\S+ )\w+", ":9 abc :10 def"),
          ['abc', 'def'])
        self.assertEqual(regex.findall(r"(?<=:\S* )\w+", ":9 abc :10 def"),
          ['abc', 'def'])
        self.assertEqual(regex.findall(r"(?<=:\S+? )\w+", ":9 abc :10 def"),
          ['abc', 'def'])
        self.assertEqual(regex.findall(r"(?<=:\S*? )\w+", ":9 abc :10 def"),
          ['abc', 'def'])

        # Hg issue 73: conditional patterns
        self.assertEqual(regex.search(r"(?:fe)?male", "female").group(),
          "female")
        self.assertEqual([m.group() for m in
          regex.finditer(r"(fe)?male: h(?(1)(er)|(is)) (\w+)",
          "female: her dog; male: his cat. asdsasda")], ['female: her dog',
          'male: his cat'])

        # Hg issue 78: "Captures" doesn't work for recursive calls
        self.assertEqual(regex.search(r'(?<rec>\((?:[^()]++|(?&rec))*\))',
          'aaa(((1+0)+1)+1)bbb').captures('rec'), ['(1+0)', '((1+0)+1)',
          '(((1+0)+1)+1)'])

        # Hg issue 80: Escape characters throws an exception
        self.assertRaisesRegex(regex.error, self.BAD_ESCAPE, lambda:
          regex.sub('x', '\\', 'x'), )

        # Hg issue 82: error range does not work
        fz = "(CAGCCTCCCATTTCAGAATATACATCC){1<e<=2}"
        seq = "tcagacgagtgcgttgtaaaacgacggccagtCAGCCTCCCATTCAGAATATACATCCcgacggccagttaaaaacaatgccaaggaggtcatagctgtttcctgccagttaaaaacaatgccaaggaggtcatagctgtttcctgacgcactcgtctgagcgggctggcaagg"
        self.assertEqual(regex.search(fz, seq, regex.BESTMATCH)[0],
          "tCAGCCTCCCATTCAGAATATACATCC")

        # Hg issue 83: slash handling in presence of a quantifier
        self.assertEqual(regex.findall(r"c..+/c", "cA/c\ncAb/c"), ['cAb/c'])

        # Hg issue 85: Non-conformance to Unicode UAX#29 re: ZWJ / ZWNJ
        self.assertEqual(ascii(regex.sub(r"(\w+)", r"[\1]",
          '\u0905\u0928\u094d\u200d\u0928 \u0d28\u0d4d\u200d \u0915\u093f\u0928',
          regex.WORD)),
          ascii('[\u0905\u0928\u094d\u200d\u0928] [\u0d28\u0d4d\u200d] [\u0915\u093f\u0928]'))

        # Hg issue 88: regex.match() hangs
        self.assertEqual(regex.match(r".*a.*ba.*aa", "ababba"), None)

        # Hg issue 87: Allow duplicate names of groups
        self.assertEqual(regex.match(r'(?<x>a(?<x>b))', "ab").spans("x"), [(1,
          2), (0, 2)])

        # Hg issue 91: match.expand is extremely slow
        # Check that the replacement cache works.
        self.assertEqual(regex.sub(r'(-)', lambda m: m.expand(r'x'), 'a-b-c'),
          'axbxc')

        # Hg issue 94: Python crashes when executing regex updates
        # pattern.findall
        rx = regex.compile(r'\bt(est){i<2}', flags=regex.V1)
        self.assertEqual(rx.search("Some text"), None)
        self.assertEqual(rx.findall("Some text"), [])

        # Hg issue 95: 'pos' for regex.error
        self.assertRaisesRegex(regex.error, self.MULTIPLE_REPEAT, lambda:
          regex.compile(r'.???'))

        # Hg issue 97: behaviour of regex.escape's special_only is wrong
        #
        # Hg issue 244: Make `special_only=True` the default in
        # `regex.escape()`
        self.assertEqual(regex.escape('foo!?', special_only=False), 'foo\\!\\?')
        self.assertEqual(regex.escape('foo!?', special_only=True), 'foo!\\?')
        self.assertEqual(regex.escape('foo!?'), 'foo!\\?')

        self.assertEqual(regex.escape(b'foo!?', special_only=False), b'foo\\!\\?')
        self.assertEqual(regex.escape(b'foo!?', special_only=True),
          b'foo!\\?')
        self.assertEqual(regex.escape(b'foo!?'), b'foo!\\?')

        # Hg issue 100: strange results from regex.search
        self.assertEqual(regex.search('^([^z]*(?:WWWi|W))?$',
          'WWWi').groups(), ('WWWi', ))
        self.assertEqual(regex.search('^([^z]*(?:WWWi|w))?$',
          'WWWi').groups(), ('WWWi', ))
        self.assertEqual(regex.search('^([^z]*?(?:WWWi|W))?$',
          'WWWi').groups(), ('WWWi', ))

        # Hg issue 101: findall() broken (seems like memory corruption)
        pat = regex.compile(r'xxx', flags=regex.FULLCASE | regex.UNICODE)
        self.assertEqual([x.group() for x in pat.finditer('yxxx')], ['xxx'])
        self.assertEqual(pat.findall('yxxx'), ['xxx'])

        raw = 'yxxx'
        self.assertEqual([x.group() for x in pat.finditer(raw)], ['xxx'])
        self.assertEqual(pat.findall(raw), ['xxx'])

        pat = regex.compile(r'xxx', flags=regex.FULLCASE | regex.IGNORECASE |
          regex.UNICODE)
        self.assertEqual([x.group() for x in pat.finditer('yxxx')], ['xxx'])
        self.assertEqual(pat.findall('yxxx'), ['xxx'])

        raw = 'yxxx'
        self.assertEqual([x.group() for x in pat.finditer(raw)], ['xxx'])
        self.assertEqual(pat.findall(raw), ['xxx'])

        # Hg issue 106: * operator not working correctly with sub()
        if sys.version_info >= (3, 7, 0):
            self.assertEqual(regex.sub('(?V0).*', 'x', 'test'), 'xx')
        else:
            self.assertEqual(regex.sub('(?V0).*', 'x', 'test'), 'x')
        self.assertEqual(regex.sub('(?V1).*', 'x', 'test'), 'xx')

        if sys.version_info >= (3, 7, 0):
            self.assertEqual(regex.sub('(?V0).*?', '|', 'test'), '|||||||||')
        else:
            self.assertEqual(regex.sub('(?V0).*?', '|', 'test'), '|t|e|s|t|')
        self.assertEqual(regex.sub('(?V1).*?', '|', 'test'), '|||||||||')

        # Hg issue 112: re: OK, but regex: SystemError
        self.assertEqual(regex.sub(r'^(@)\n(?!.*?@)(.*)',
          r'\1\n==========\n\2', '@\n', flags=regex.DOTALL), '@\n==========\n')

        # Hg issue 109: Edit distance of fuzzy match
        self.assertEqual(regex.match(r'(?:cats|cat){e<=1}',
         'caz').fuzzy_counts, (1, 0, 0))
        self.assertEqual(regex.match(r'(?e)(?:cats|cat){e<=1}',
          'caz').fuzzy_counts, (1, 0, 0))
        self.assertEqual(regex.match(r'(?b)(?:cats|cat){e<=1}',
          'caz').fuzzy_counts, (1, 0, 0))

        self.assertEqual(regex.match(r'(?:cat){e<=1}', 'caz').fuzzy_counts,
          (1, 0, 0))
        self.assertEqual(regex.match(r'(?e)(?:cat){e<=1}',
          'caz').fuzzy_counts, (1, 0, 0))
        self.assertEqual(regex.match(r'(?b)(?:cat){e<=1}',
          'caz').fuzzy_counts, (1, 0, 0))

        self.assertEqual(regex.match(r'(?:cats){e<=2}', 'c ats').fuzzy_counts,
          (1, 1, 0))
        self.assertEqual(regex.match(r'(?e)(?:cats){e<=2}',
          'c ats').fuzzy_counts, (0, 1, 0))
        self.assertEqual(regex.match(r'(?b)(?:cats){e<=2}',
          'c ats').fuzzy_counts, (0, 1, 0))

        self.assertEqual(regex.match(r'(?:cats){e<=2}',
          'c a ts').fuzzy_counts, (0, 2, 0))
        self.assertEqual(regex.match(r'(?e)(?:cats){e<=2}',
          'c a ts').fuzzy_counts, (0, 2, 0))
        self.assertEqual(regex.match(r'(?b)(?:cats){e<=2}',
          'c a ts').fuzzy_counts, (0, 2, 0))

        self.assertEqual(regex.match(r'(?:cats){e<=1}', 'c ats').fuzzy_counts,
          (0, 1, 0))
        self.assertEqual(regex.match(r'(?e)(?:cats){e<=1}',
          'c ats').fuzzy_counts, (0, 1, 0))
        self.assertEqual(regex.match(r'(?b)(?:cats){e<=1}',
          'c ats').fuzzy_counts, (0, 1, 0))

        # Hg issue 115: Infinite loop when processing backreferences
        self.assertEqual(regex.findall(r'\bof ([a-z]+) of \1\b',
          'To make use of one of these modules'), [])

        # Hg issue 125: Reference to entire match (\g&lt;0&gt;) in
        # Pattern.sub() doesn't work as of 2014.09.22 release.
        self.assertEqual(regex.sub(r'x', r'\g<0>', 'x'), 'x')

        # Unreported issue: no such builtin as 'ascii' in Python 2.
        self.assertEqual(bool(regex.match(r'a', 'a', regex.DEBUG)), True)

        # Hg issue 131: nested sets behaviour
        self.assertEqual(regex.findall(r'(?V1)[[b-e]--cd]', 'abcdef'), ['b',
          'e'])
        self.assertEqual(regex.findall(r'(?V1)[b-e--cd]', 'abcdef'), ['b',
          'e'])
        self.assertEqual(regex.findall(r'(?V1)[[bcde]--cd]', 'abcdef'), ['b',
          'e'])
        self.assertEqual(regex.findall(r'(?V1)[bcde--cd]', 'abcdef'), ['b',
          'e'])

        # Hg issue 132: index out of range on null property \p{}
        self.assertRaisesRegex(regex.error, '^unknown property at position 4$',
          lambda: regex.compile(r'\p{}'))

        # Issue 23692.
        self.assertEqual(regex.match('(?:()|(?(1)()|z)){2}(?(2)a|z)',
          'a').group(0, 1, 2), ('a', '', ''))
        self.assertEqual(regex.match('(?:()|(?(1)()|z)){0,2}(?(2)a|z)',
          'a').group(0, 1, 2), ('a', '', ''))

        # Hg issue 137: Posix character class :punct: does not seem to be
        # supported.

        # Posix compatibility as recommended here:
        # http://www.unicode.org/reports/tr18/#Compatibility_Properties

        # Posix in Unicode.
        chars = ''.join(chr(c) for c in range(0x10000))

        self.assertEqual(ascii(''.join(regex.findall(r'''[[:alnum:]]+''',
          chars))), ascii(''.join(regex.findall(r'''[\p{Alpha}\p{PosixDigit}]+''',
          chars))))
        self.assertEqual(ascii(''.join(regex.findall(r'''[[:alpha:]]+''',
          chars))), ascii(''.join(regex.findall(r'''\p{Alpha}+''',
          chars))))
        self.assertEqual(ascii(''.join(regex.findall(r'''[[:ascii:]]+''',
          chars))), ascii(''.join(regex.findall(r'''[\p{InBasicLatin}]+''',
          chars))))
        self.assertEqual(ascii(''.join(regex.findall(r'''[[:blank:]]+''',
          chars))), ascii(''.join(regex.findall(r'''[\p{gc=Space_Separator}\t]+''',
          chars))))
        self.assertEqual(ascii(''.join(regex.findall(r'''[[:cntrl:]]+''',
          chars))), ascii(''.join(regex.findall(r'''\p{gc=Control}+''', chars))))
        self.assertEqual(ascii(''.join(regex.findall(r'''[[:digit:]]+''',
          chars))), ascii(''.join(regex.findall(r'''[0-9]+''', chars))))
        self.assertEqual(ascii(''.join(regex.findall(r'''[[:graph:]]+''',
          chars))), ascii(''.join(regex.findall(r'''[^\p{Space}\p{gc=Control}\p{gc=Surrogate}\p{gc=Unassigned}]+''',
          chars))))
        self.assertEqual(ascii(''.join(regex.findall(r'''[[:lower:]]+''',
          chars))), ascii(''.join(regex.findall(r'''\p{Lower}+''',
          chars))))
        self.assertEqual(ascii(''.join(regex.findall(r'''[[:print:]]+''',
          chars))), ascii(''.join(regex.findall(r'''(?V1)[\p{Graph}\p{Blank}--\p{Cntrl}]+''', chars))))
        self.assertEqual(ascii(''.join(regex.findall(r'''[[:punct:]]+''',
          chars))),
          ascii(''.join(regex.findall(r'''(?V1)[\p{gc=Punctuation}\p{gc=Symbol}--\p{Alpha}]+''',
          chars))))
        self.assertEqual(ascii(''.join(regex.findall(r'''[[:space:]]+''',
          chars))), ascii(''.join(regex.findall(r'''\p{Whitespace}+''',
          chars))))
        self.assertEqual(ascii(''.join(regex.findall(r'''[[:upper:]]+''',
          chars))), ascii(''.join(regex.findall(r'''\p{Upper}+''',
          chars))))
        self.assertEqual(ascii(''.join(regex.findall(r'''[[:word:]]+''',
          chars))), ascii(''.join(regex.findall(r'''[\p{Alpha}\p{gc=Mark}\p{Digit}\p{gc=Connector_Punctuation}\p{Join_Control}]+''',
          chars))))
        self.assertEqual(ascii(''.join(regex.findall(r'''[[:xdigit:]]+''',
          chars))), ascii(''.join(regex.findall(r'''[0-9A-Fa-f]+''',
          chars))))

        # Posix in ASCII.
        chars = bytes(range(0x100))

        self.assertEqual(ascii(b''.join(regex.findall(br'''(?a)[[:alnum:]]+''',
          chars))), ascii(b''.join(regex.findall(br'''(?a)[\p{Alpha}\p{PosixDigit}]+''',
          chars))))
        self.assertEqual(ascii(b''.join(regex.findall(br'''(?a)[[:alpha:]]+''',
          chars))), ascii(b''.join(regex.findall(br'''(?a)\p{Alpha}+''', chars))))
        self.assertEqual(ascii(b''.join(regex.findall(br'''(?a)[[:ascii:]]+''',
          chars))), ascii(b''.join(regex.findall(br'''(?a)[\x00-\x7F]+''', chars))))
        self.assertEqual(ascii(b''.join(regex.findall(br'''(?a)[[:blank:]]+''',
          chars))), ascii(b''.join(regex.findall(br'''(?a)[\p{gc=Space_Separator}\t]+''',
          chars))))
        self.assertEqual(ascii(b''.join(regex.findall(br'''(?a)[[:cntrl:]]+''',
          chars))), ascii(b''.join(regex.findall(br'''(?a)\p{gc=Control}+''',
          chars))))
        self.assertEqual(ascii(b''.join(regex.findall(br'''(?a)[[:digit:]]+''',
          chars))), ascii(b''.join(regex.findall(br'''(?a)[0-9]+''', chars))))
        self.assertEqual(ascii(b''.join(regex.findall(br'''(?a)[[:graph:]]+''',
          chars))), ascii(b''.join(regex.findall(br'''(?a)[^\p{Space}\p{gc=Control}\p{gc=Surrogate}\p{gc=Unassigned}]+''', chars))))
        self.assertEqual(ascii(b''.join(regex.findall(br'''(?a)[[:lower:]]+''',
          chars))), ascii(b''.join(regex.findall(br'''(?a)\p{Lower}+''', chars))))
        self.assertEqual(ascii(b''.join(regex.findall(br'''(?a)[[:print:]]+''',
          chars))), ascii(b''.join(regex.findall(br'''(?aV1)[\p{Graph}\p{Blank}--\p{Cntrl}]+''', chars))))
        self.assertEqual(ascii(b''.join(regex.findall(br'''(?a)[[:punct:]]+''',
          chars))), ascii(b''.join(regex.findall(br'''(?aV1)[\p{gc=Punctuation}\p{gc=Symbol}--\p{Alpha}]+''',
          chars))))
        self.assertEqual(ascii(b''.join(regex.findall(br'''(?a)[[:space:]]+''',
          chars))), ascii(b''.join(regex.findall(br'''(?a)\p{Whitespace}+''', chars))))
        self.assertEqual(ascii(b''.join(regex.findall(br'''(?a)[[:upper:]]+''',
          chars))), ascii(b''.join(regex.findall(br'''(?a)\p{Upper}+''', chars))))
        self.assertEqual(ascii(b''.join(regex.findall(br'''(?a)[[:word:]]+''',
          chars))), ascii(b''.join(regex.findall(br'''(?a)[\p{Alpha}\p{gc=Mark}\p{Digit}\p{gc=Connector_Punctuation}\p{Join_Control}]+''', chars))))
        self.assertEqual(ascii(b''.join(regex.findall(br'''(?a)[[:xdigit:]]+''',
          chars))), ascii(b''.join(regex.findall(br'''(?a)[0-9A-Fa-f]+''', chars))))

        # Hg issue 138: grapheme anchored search not working properly.
        self.assertEqual(ascii(regex.search(r'\X$', 'ab\u2103').group()),
          ascii('\u2103'))

        # Hg issue 139: Regular expression with multiple wildcards where first
        # should match empty string does not always work.
        self.assertEqual(regex.search("([^L]*)([^R]*R)", "LtR").groups(), ('',
          'LtR'))

        # Hg issue 140: Replace with REVERSE and groups has unexpected
        # behavior.
        self.assertEqual(regex.sub(r'(.)', r'x\1y', 'ab'), 'xayxby')
        self.assertEqual(regex.sub(r'(?r)(.)', r'x\1y', 'ab'), 'xayxby')
        self.assertEqual(regex.subf(r'(.)', 'x{1}y', 'ab'), 'xayxby')
        self.assertEqual(regex.subf(r'(?r)(.)', 'x{1}y', 'ab'), 'xayxby')

        # Hg issue 141: Crash on a certain partial match.
        self.assertEqual(regex.fullmatch('(a)*abc', 'ab',
          partial=True).span(), (0, 2))
        self.assertEqual(regex.fullmatch('(a)*abc', 'ab',
          partial=True).partial, True)

        # Hg issue 143: Partial matches have incorrect span if prefix is '.'
        # wildcard.
        self.assertEqual(regex.search('OXRG', 'OOGOX', partial=True).span(),
          (3, 5))
        self.assertEqual(regex.search('.XRG', 'OOGOX', partial=True).span(),
          (3, 5))
        self.assertEqual(regex.search('.{1,3}XRG', 'OOGOX',
          partial=True).span(), (1, 5))

        # Hg issue 144: Latest version problem with matching 'R|R'.
        self.assertEqual(regex.match('R|R', 'R').span(), (0, 1))

        # Hg issue 146: Forced-fail (?!) works improperly in conditional.
        self.assertEqual(regex.match(r'(.)(?(1)(?!))', 'xy'), None)

        # Groups cleared after failure.
        self.assertEqual(regex.findall(r'(y)?(\d)(?(1)\b\B)', 'ax1y2z3b'),
          [('', '1'), ('', '2'), ('', '3')])
        self.assertEqual(regex.findall(r'(y)?+(\d)(?(1)\b\B)', 'ax1y2z3b'),
          [('', '1'), ('', '2'), ('', '3')])

        # Hg issue 147: Fuzzy match can return match points beyond buffer end.
        self.assertEqual([m.span() for m in regex.finditer(r'(?i)(?:error){e}',
          'regex failure')], [(0, 5), (5, 10), (10, 13), (13, 13)])
        self.assertEqual([m.span() for m in
          regex.finditer(r'(?fi)(?:error){e}', 'regex failure')], [(0, 5), (5,
          10), (10, 13), (13, 13)])

        # Hg issue 150: Have an option for POSIX-compatible longest match of
        # alternates.
        self.assertEqual(regex.search(r'(?p)\d+(\w(\d*)?|[eE]([+-]\d+))',
          '10b12')[0], '10b12')
        self.assertEqual(regex.search(r'(?p)\d+(\w(\d*)?|[eE]([+-]\d+))',
          '10E+12')[0], '10E+12')

        self.assertEqual(regex.search(r'(?p)(\w|ae|oe|ue|ss)', 'ae')[0], 'ae')
        self.assertEqual(regex.search(r'(?p)one(self)?(selfsufficient)?',
          'oneselfsufficient')[0], 'oneselfsufficient')

        # Hg issue 151: Request: \K.
        self.assertEqual(regex.search(r'(ab\Kcd)', 'abcd').group(0, 1), ('cd',
          'abcd'))
        self.assertEqual(regex.findall(r'\w\w\K\w\w', 'abcdefgh'), ['cd',
          'gh'])
        self.assertEqual(regex.findall(r'(\w\w\K\w\w)', 'abcdefgh'), ['abcd',
          'efgh'])

        self.assertEqual(regex.search(r'(?r)(ab\Kcd)', 'abcd').group(0, 1),
          ('ab', 'abcd'))
        self.assertEqual(regex.findall(r'(?r)\w\w\K\w\w', 'abcdefgh'), ['ef',
          'ab'])
        self.assertEqual(regex.findall(r'(?r)(\w\w\K\w\w)', 'abcdefgh'),
          ['efgh', 'abcd'])

        # Hg issue 152: Request: Request: (?(DEFINE)...).
        self.assertEqual(regex.search(r'(?(DEFINE)(?<quant>\d+)(?<item>\w+))(?&quant) (?&item)',
          '5 elephants')[0], '5 elephants')

        self.assertEqual(regex.search(r'(?&routine)(?(DEFINE)(?<routine>.))', 'a').group('routine'), None)
        self.assertEqual(regex.search(r'(?&routine)(?(DEFINE)(?<routine>.))', 'a').captures('routine'), ['a'])

        # Hg issue 153: Request: (*SKIP).
        self.assertEqual(regex.search(r'12(*FAIL)|3', '123')[0], '3')
        self.assertEqual(regex.search(r'(?r)12(*FAIL)|3', '123')[0], '3')

        self.assertEqual(regex.search(r'\d+(*PRUNE)\d', '123'), None)
        self.assertEqual(regex.search(r'\d+(?=(*PRUNE))\d', '123')[0], '123')
        self.assertEqual(regex.search(r'\d+(*PRUNE)bcd|[3d]', '123bcd')[0],
          '123bcd')
        self.assertEqual(regex.search(r'\d+(*PRUNE)bcd|[3d]', '123zzd')[0],
          'd')
        self.assertEqual(regex.search(r'\d+?(*PRUNE)bcd|[3d]', '123bcd')[0],
          '3bcd')
        self.assertEqual(regex.search(r'\d+?(*PRUNE)bcd|[3d]', '123zzd')[0],
          'd')
        self.assertEqual(regex.search(r'\d++(?<=3(*PRUNE))zzd|[4d]$',
          '123zzd')[0], '123zzd')
        self.assertEqual(regex.search(r'\d++(?<=3(*PRUNE))zzd|[4d]$',
          '124zzd')[0], 'd')
        self.assertEqual(regex.search(r'\d++(?<=(*PRUNE)3)zzd|[4d]$',
          '124zzd')[0], 'd')
        self.assertEqual(regex.search(r'\d++(?<=2(*PRUNE)3)zzd|[3d]$',
          '124zzd')[0], 'd')

        self.assertEqual(regex.search(r'(?r)\d(*PRUNE)\d+', '123'), None)
        self.assertEqual(regex.search(r'(?r)\d(?<=(*PRUNE))\d+', '123')[0],
          '123')
        self.assertEqual(regex.search(r'(?r)\d+(*PRUNE)bcd|[3d]',
          '123bcd')[0], '123bcd')
        self.assertEqual(regex.search(r'(?r)\d+(*PRUNE)bcd|[3d]',
          '123zzd')[0], 'd')
        self.assertEqual(regex.search(r'(?r)\d++(?<=3(*PRUNE))zzd|[4d]$',
          '123zzd')[0], '123zzd')
        self.assertEqual(regex.search(r'(?r)\d++(?<=3(*PRUNE))zzd|[4d]$',
          '124zzd')[0], 'd')
        self.assertEqual(regex.search(r'(?r)\d++(?<=(*PRUNE)3)zzd|[4d]$',
          '124zzd')[0], 'd')
        self.assertEqual(regex.search(r'(?r)\d++(?<=2(*PRUNE)3)zzd|[3d]$',
          '124zzd')[0], 'd')

        self.assertEqual(regex.search(r'\d+(*SKIP)bcd|[3d]', '123bcd')[0],
          '123bcd')
        self.assertEqual(regex.search(r'\d+(*SKIP)bcd|[3d]', '123zzd')[0],
          'd')
        self.assertEqual(regex.search(r'\d+?(*SKIP)bcd|[3d]', '123bcd')[0],
          '3bcd')
        self.assertEqual(regex.search(r'\d+?(*SKIP)bcd|[3d]', '123zzd')[0],
          'd')
        self.assertEqual(regex.search(r'\d++(?<=3(*SKIP))zzd|[4d]$',
          '123zzd')[0], '123zzd')
        self.assertEqual(regex.search(r'\d++(?<=3(*SKIP))zzd|[4d]$',
          '124zzd')[0], 'd')
        self.assertEqual(regex.search(r'\d++(?<=(*SKIP)3)zzd|[4d]$',
          '124zzd')[0], 'd')
        self.assertEqual(regex.search(r'\d++(?<=2(*SKIP)3)zzd|[3d]$',
          '124zzd')[0], 'd')

        self.assertEqual(regex.search(r'(?r)\d+(*SKIP)bcd|[3d]', '123bcd')[0],
          '123bcd')
        self.assertEqual(regex.search(r'(?r)\d+(*SKIP)bcd|[3d]', '123zzd')[0],
          'd')
        self.assertEqual(regex.search(r'(?r)\d++(?<=3(*SKIP))zzd|[4d]$',
          '123zzd')[0], '123zzd')
        self.assertEqual(regex.search(r'(?r)\d++(?<=3(*SKIP))zzd|[4d]$',
          '124zzd')[0], 'd')
        self.assertEqual(regex.search(r'(?r)\d++(?<=(*SKIP)3)zzd|[4d]$',
          '124zzd')[0], 'd')
        self.assertEqual(regex.search(r'(?r)\d++(?<=2(*SKIP)3)zzd|[3d]$',
          '124zzd')[0], 'd')

        # Hg issue 154: Segmentation fault 11 when working with an atomic group
        text = """June 30, December 31, 2013 2012
some words follow:
more words and numbers 1,234,567 9,876,542
more words and numbers 1,234,567 9,876,542"""
        self.assertEqual(len(regex.findall(r'(?<!\d)(?>2014|2013 ?2012)', text)), 1)

        # Hg issue 156: regression on atomic grouping
        self.assertEqual(regex.match('1(?>2)', '12').span(), (0, 2))

        # Hg issue 157: regression: segfault on complex lookaround
        self.assertEqual(regex.match(r'(?V1w)(?=(?=[^A-Z]*+[A-Z])(?=[^a-z]*+[a-z]))(?=\D*+\d)(?=\p{Alphanumeric}*+\P{Alphanumeric})\A(?s:.){8,255}+\Z',
          'AAaa11!!')[0], 'AAaa11!!')

        # Hg issue 158: Group issue with (?(DEFINE)...)
        TEST_REGEX = regex.compile(r'''(?smx)
(?(DEFINE)
  (?<subcat>
   ^,[^,]+,
   )
)

# Group 2 is defined on this line
^,([^,]+),

(?:(?!(?&subcat)[\r\n]+(?&subcat)).)+
''')

        TEST_DATA = '''
,Cat 1,
,Brand 1,
some
thing
,Brand 2,
other
things
,Cat 2,
,Brand,
Some
thing
'''

        self.assertEqual([m.span(1, 2) for m in
          TEST_REGEX.finditer(TEST_DATA)], [((-1, -1), (2, 7)), ((-1, -1), (54,
          59))])

        # Hg issue 161: Unexpected fuzzy match results
        self.assertEqual(regex.search('(abcdefgh){e}',
          '******abcdefghijklmnopqrtuvwxyz', regex.BESTMATCH).span(), (6, 14))
        self.assertEqual(regex.search('(abcdefghi){e}',
          '******abcdefghijklmnopqrtuvwxyz', regex.BESTMATCH).span(), (6, 15))

        # Hg issue 163: allow lookarounds in conditionals.
        self.assertEqual(regex.match(r'(?:(?=\d)\d+\b|\w+)', '123abc').span(),
          (0, 6))
        self.assertEqual(regex.match(r'(?(?=\d)\d+\b|\w+)', '123abc'), None)
        self.assertEqual(regex.search(r'(?(?<=love\s)you|(?<=hate\s)her)',
          "I love you").span(), (7, 10))
        self.assertEqual(regex.findall(r'(?(?<=love\s)you|(?<=hate\s)her)',
          "I love you but I don't hate her either"), ['you', 'her'])

        # Hg issue 180: bug of POSIX matching.
        self.assertEqual(regex.search(r'(?p)a*(.*?)', 'aaabbb').group(0, 1),
          ('aaabbb', 'bbb'))
        self.assertEqual(regex.search(r'(?p)a*(.*)', 'aaabbb').group(0, 1),
          ('aaabbb', 'bbb'))
        self.assertEqual(regex.sub(r'(?p)a*(.*?)', r'\1', 'aaabbb'), 'bbb')
        self.assertEqual(regex.sub(r'(?p)a*(.*)', r'\1', 'aaabbb'), 'bbb')

        # Hg issue 192: Named lists reverse matching doesn't work with
        # IGNORECASE and V1
        self.assertEqual(regex.match(r'(?irV0)\L<kw>', '21', kw=['1']).span(),
          (1, 2))
        self.assertEqual(regex.match(r'(?irV1)\L<kw>', '21', kw=['1']).span(),
          (1, 2))

        # Hg issue 193: Alternation and .REVERSE flag.
        self.assertEqual(regex.search('a|b', '111a222').span(), (3, 4))
        self.assertEqual(regex.search('(?r)a|b', '111a222').span(), (3, 4))

        # Hg issue 194: .FULLCASE and Backreference
        self.assertEqual(regex.search(r'(?if)<(CLI)><\1>',
          '<cli><cli>').span(), (0, 10))
        self.assertEqual(regex.search(r'(?if)<(CLI)><\1>',
          '<cli><clI>').span(), (0, 10))
        self.assertEqual(regex.search(r'(?ifr)<\1><(CLI)>',
          '<cli><clI>').span(), (0, 10))

        # Hg issue 195: Pickle (or otherwise serial) the compiled regex
        r = regex.compile(r'\L<options>', options=['foo', 'bar'])
        p = pickle.dumps(r)
        r = pickle.loads(p)
        self.assertEqual(r.match('foo').span(), (0, 3))

        # Hg issue 196: Fuzzy matching on repeated regex not working as
        # expected
        self.assertEqual(regex.match('(x{6}){e<=1}', 'xxxxxx',
          flags=regex.BESTMATCH).span(), (0, 6))
        self.assertEqual(regex.match('(x{6}){e<=1}', 'xxxxx',
          flags=regex.BESTMATCH).span(), (0, 5))
        self.assertEqual(regex.match('(x{6}){e<=1}', 'x',
          flags=regex.BESTMATCH), None)
        self.assertEqual(regex.match('(?r)(x{6}){e<=1}', 'xxxxxx',
          flags=regex.BESTMATCH).span(), (0, 6))
        self.assertEqual(regex.match('(?r)(x{6}){e<=1}', 'xxxxx',
          flags=regex.BESTMATCH).span(), (0, 5))
        self.assertEqual(regex.match('(?r)(x{6}){e<=1}', 'x',
          flags=regex.BESTMATCH), None)

        # Hg issue 197: ValueError in regex.compile
        self.assertRaises(regex.error, lambda:
          regex.compile(b'00000\\0\\00\\^\50\\00\\U05000000'))

        # Hg issue 198: ValueError in regex.compile
        self.assertRaises(regex.error, lambda: regex.compile(b"{e<l"))

        # Hg issue 199: Segfault in re.compile
        self.assertEqual(bool(regex.compile('((?0)){e}')), True)

        # Hg issue 200: AttributeError in regex.compile with latest regex
        self.assertEqual(bool(regex.compile('\x00?(?0){e}')), True)

        # Hg issue 201: ENHANCEMATCH crashes interpreter
        self.assertEqual(regex.findall(r'((brown)|(lazy)){1<=e<=3} ((dog)|(fox)){1<=e<=3}',
          'The quick borwn fax jumped over the lzy hog', regex.ENHANCEMATCH),
          [('borwn', 'borwn', '', 'fax', '', 'fax'), ('lzy', '', 'lzy', 'hog',
          'hog', '')])

        # Hg issue 203: partial matching bug
        self.assertEqual(regex.search(r'\d\d\d-\d\d-\d\d\d\d',
          "My SSN is 999-89-76, but don't tell.", partial=True).span(), (36,
          36))

        # Hg issue 204: confusion of (?aif) flags
        upper_i = '\N{CYRILLIC CAPITAL LETTER SHORT I}'
        lower_i = '\N{CYRILLIC SMALL LETTER SHORT I}'

        self.assertEqual(bool(regex.match(r'(?ui)' + upper_i,
          lower_i)), True)
        self.assertEqual(bool(regex.match(r'(?ui)' + lower_i,
          upper_i)), True)

        self.assertEqual(bool(regex.match(r'(?ai)' + upper_i,
          lower_i)), False)
        self.assertEqual(bool(regex.match(r'(?ai)' + lower_i,
          upper_i)), False)

        self.assertEqual(bool(regex.match(r'(?afi)' + upper_i,
          lower_i)), False)
        self.assertEqual(bool(regex.match(r'(?afi)' + lower_i,
          upper_i)), False)

        # Hg issue 205: Named list and (?ri) flags
        self.assertEqual(bool(regex.search(r'(?i)\L<aa>', '22', aa=['121',
          '22'])), True)
        self.assertEqual(bool(regex.search(r'(?ri)\L<aa>', '22', aa=['121',
          '22'])), True)
        self.assertEqual(bool(regex.search(r'(?fi)\L<aa>', '22', aa=['121',
          '22'])), True)
        self.assertEqual(bool(regex.search(r'(?fri)\L<aa>', '22', aa=['121',
          '22'])), True)

        # Hg issue 208: Named list, (?ri) flags, Backreference
        self.assertEqual(regex.search(r'(?r)\1dog..(?<=(\L<aa>))$', 'ccdogcc',
          aa=['bcb', 'cc']). span(), (0, 7))
        self.assertEqual(regex.search(r'(?ir)\1dog..(?<=(\L<aa>))$',
          'ccdogcc', aa=['bcb', 'cc']). span(), (0, 7))

        # Hg issue 210: Fuzzy matching and Backreference
        self.assertEqual(regex.search(r'(2)(?:\1{5}){e<=1}',
          '3222212').span(), (1, 7))
        self.assertEqual(regex.search(r'(\d)(?:\1{5}){e<=1}',
          '3222212').span(), (1, 7))

        # Hg issue 211: Segmentation fault with recursive matches and atomic
        # groups
        self.assertEqual(regex.match(r'''\A(?P<whole>(?>\((?&whole)\)|[+\-]))\Z''',
          '((-))').span(), (0, 5))
        self.assertEqual(regex.match(r'''\A(?P<whole>(?>\((?&whole)\)|[+\-]))\Z''',
          '((-)+)'), None)

        # Hg issue 212: Unexpected matching difference with .*? between re and
        # regex
        self.assertEqual(regex.match(r"x.*? (.).*\1(.*)\1",
          'x  |y| z|').span(), (0, 9))
        self.assertEqual(regex.match(r"\.sr (.*?) (.)(.*)\2(.*)\2(.*)",
          r'.sr  h |<nw>|<span class="locked">|').span(), (0, 35))

        # Hg issue 213: Segmentation Fault
        a = '"\\xF9\\x80\\xAEqdz\\x95L\\xA7\\x89[\\xFE \\x91)\\xF9]\\xDB\'\\x99\\x09=\\x00\\xFD\\x98\\x22\\xDD\\xF1\\xB6\\xC3 Z\\xB6gv\\xA5x\\x93P\\xE1r\\x14\\x8Cv\\x0C\\xC0w\\x15r\\xFFc%" '
        py_regex_pattern = r'''(?P<http_referer>((?>(?<!\\)(?>"(?>\\.|[^\\"]+)+"|""|(?>'(?>\\.|[^\\']+)+')|''|(?>`(?>\\.|[^\\`]+)+`)|``)))) (?P<useragent>((?>(?<!\\)(?>"(?>\\.|[^\\"]+)+"|""|(?>'(?>\\.|[^\\']+)+')|''|(?>`(?>\\.|[^\\`]+)+`)|``))))'''
        self.assertEqual(bool(regex.search(py_regex_pattern, a)), False)

        # Hg Issue 216: Invalid match when using negative lookbehind and pipe
        self.assertEqual(bool(regex.match('foo(?<=foo)', 'foo')), True)
        self.assertEqual(bool(regex.match('foo(?<!foo)', 'foo')), False)
        self.assertEqual(bool(regex.match('foo(?<=foo|x)', 'foo')), True)
        self.assertEqual(bool(regex.match('foo(?<!foo|x)', 'foo')), False)

        # Hg issue 217: Core dump in conditional ahead match and matching \!
        # character
        self.assertEqual(bool(regex.match(r'(?(?=.*\!.*)(?P<true>.*\!\w*\:.*)|(?P<false>.*))',
          '!')), False)

        # Hg issue 220: Misbehavior of group capture with OR operand
        self.assertEqual(regex.match(r'\w*(ea)\w*|\w*e(?!a)\w*',
          'easier').groups(), ('ea', ))

        # Hg issue 225: BESTMATCH in fuzzy match not working
        self.assertEqual(regex.search('(^1234$){i,d}', '12234',
          regex.BESTMATCH).span(), (0, 5))
        self.assertEqual(regex.search('(^1234$){i,d}', '12234',
          regex.BESTMATCH).fuzzy_counts, (0, 1, 0))

        self.assertEqual(regex.search('(^1234$){s,i,d}', '12234',
          regex.BESTMATCH).span(), (0, 5))
        self.assertEqual(regex.search('(^1234$){s,i,d}', '12234',
          regex.BESTMATCH).fuzzy_counts, (0, 1, 0))

        # Hg issue 226: Error matching at start of string
        self.assertEqual(regex.search('(^123$){s,i,d}', 'xxxxxxxx123',
          regex.BESTMATCH).span(), (0, 11))
        self.assertEqual(regex.search('(^123$){s,i,d}', 'xxxxxxxx123',
          regex.BESTMATCH).fuzzy_counts, (0, 8, 0))

        # Hg issue 227: Incorrect behavior for ? operator with UNICODE +
        # IGNORECASE
        self.assertEqual(regex.search(r'a?yz', 'xxxxyz', flags=regex.FULLCASE |
          regex.IGNORECASE).span(), (4, 6))

        # Hg issue 230: Is it a bug of (?(DEFINE)...)
        self.assertEqual(regex.findall(r'(?:(?![a-d]).)+', 'abcdefgh'),
          ['efgh'])
        self.assertEqual(regex.findall(r'''(?(DEFINE)(?P<mydef>(?:(?![a-d]).)))(?&mydef)+''',
          'abcdefgh'), ['efgh'])

        # Hg issue 238: Not fully re backward compatible
        self.assertEqual(regex.findall(r'((\w{1,3})(\.{2,10})){1,3}',
          '"Erm....yes. T..T...Thank you for that."'), [('Erm....', 'Erm',
          '....'), ('T...', 'T', '...')])
        self.assertEqual(regex.findall(r'((\w{1,3})(\.{2,10})){3}',
          '"Erm....yes. T..T...Thank you for that."'), [])
        self.assertEqual(regex.findall(r'((\w{1,3})(\.{2,10})){2}',
          '"Erm....yes. T..T...Thank you for that."'), [('T...', 'T', '...')])
        self.assertEqual(regex.findall(r'((\w{1,3})(\.{2,10})){1}',
          '"Erm....yes. T..T...Thank you for that."'), [('Erm....', 'Erm',
          '....'), ('T..', 'T', '..'), ('T...', 'T', '...')])

        # Hg issue 247: Unexpected result with fuzzy matching and lookahead
        # expression
        self.assertEqual(regex.search(r'(?:ESTONIA(?!\w)){e<=1}',
          'ESTONIAN WORKERS').group(), 'ESTONIAN')
        self.assertEqual(regex.search(r'(?:ESTONIA(?=\W)){e<=1}',
          'ESTONIAN WORKERS').group(), 'ESTONIAN')

        self.assertEqual(regex.search(r'(?:(?<!\w)ESTONIA){e<=1}',
          'BLUB NESTONIA').group(), 'NESTONIA')
        self.assertEqual(regex.search(r'(?:(?<=\W)ESTONIA){e<=1}',
          'BLUB NESTONIA').group(), 'NESTONIA')

        self.assertEqual(regex.search(r'(?r)(?:ESTONIA(?!\w)){e<=1}',
          'ESTONIAN WORKERS').group(), 'ESTONIAN')
        self.assertEqual(regex.search(r'(?r)(?:ESTONIA(?=\W)){e<=1}',
          'ESTONIAN WORKERS').group(), 'ESTONIAN')

        self.assertEqual(regex.search(r'(?r)(?:(?<!\w)ESTONIA){e<=1}',
          'BLUB NESTONIA').group(), 'NESTONIA')
        self.assertEqual(regex.search(r'(?r)(?:(?<=\W)ESTONIA){e<=1}',
          'BLUB NESTONIA').group(), 'NESTONIA')

        # Hg issue 248: Unexpected result with fuzzy matching and more than one
        # non-greedy quantifier
        self.assertEqual(regex.search(r'(?:A.*B.*CDE){e<=2}',
          'A B CYZ').group(), 'A B CYZ')
        self.assertEqual(regex.search(r'(?:A.*B.*?CDE){e<=2}',
          'A B CYZ').group(), 'A B CYZ')
        self.assertEqual(regex.search(r'(?:A.*?B.*CDE){e<=2}',
          'A B CYZ').group(), 'A B CYZ')
        self.assertEqual(regex.search(r'(?:A.*?B.*?CDE){e<=2}',
          'A B CYZ').group(), 'A B CYZ')

        # Hg issue 249: Add an option to regex.escape() to not escape spaces
        self.assertEqual(regex.escape(' ,0A[', special_only=False, literal_spaces=False), '\\ \\,0A\\[')
        self.assertEqual(regex.escape(' ,0A[', special_only=False, literal_spaces=True), ' \\,0A\\[')
        self.assertEqual(regex.escape(' ,0A[', special_only=True, literal_spaces=False), '\\ ,0A\\[')
        self.assertEqual(regex.escape(' ,0A[', special_only=True, literal_spaces=True), ' ,0A\\[')

        self.assertEqual(regex.escape(' ,0A['), '\\ ,0A\\[')

        # Hg issue 251: Segfault with a particular expression
        self.assertEqual(regex.search(r'(?(?=A)A|B)', 'A').span(), (0, 1))
        self.assertEqual(regex.search(r'(?(?=A)A|B)', 'B').span(), (0, 1))
        self.assertEqual(regex.search(r'(?(?=A)A|)', 'B').span(), (0, 0))
        self.assertEqual(regex.search(r'(?(?=X)X|)', '').span(), (0, 0))
        self.assertEqual(regex.search(r'(?(?=X))', '').span(), (0, 0))

        # Hg issue 252: Empty capture strings when using DEFINE group reference
        # within look-behind expression
        self.assertEqual(regex.search(r'(?(DEFINE)(?<func>.))(?&func)',
          'abc').groups(), (None, ))
        self.assertEqual(regex.search(r'(?(DEFINE)(?<func>.))(?&func)',
          'abc').groupdict(), {'func': None})
        self.assertEqual(regex.search(r'(?(DEFINE)(?<func>.))(?&func)',
          'abc').capturesdict(), {'func': ['a']})

        self.assertEqual(regex.search(r'(?(DEFINE)(?<func>.))(?=(?&func))',
          'abc').groups(), (None, ))
        self.assertEqual(regex.search(r'(?(DEFINE)(?<func>.))(?=(?&func))',
          'abc').groupdict(), {'func': None})
        self.assertEqual(regex.search(r'(?(DEFINE)(?<func>.))(?=(?&func))',
          'abc').capturesdict(), {'func': ['a']})

        self.assertEqual(regex.search(r'(?(DEFINE)(?<func>.)).(?<=(?&func))',
          'abc').groups(), (None, ))
        self.assertEqual(regex.search(r'(?(DEFINE)(?<func>.)).(?<=(?&func))',
          'abc').groupdict(), {'func': None})
        self.assertEqual(regex.search(r'(?(DEFINE)(?<func>.)).(?<=(?&func))',
          'abc').capturesdict(), {'func': ['a']})

        # Hg issue 271: Comment logic different between Re and Regex
        self.assertEqual(bool(regex.match(r'ab(?#comment\))cd', 'abcd')), True)

        # Hg issue 276: Partial Matches yield incorrect matches and bounds
        self.assertEqual(regex.search(r'[a-z]+ [a-z]*?:', 'foo bar',
          partial=True).span(), (0, 7))
        self.assertEqual(regex.search(r'(?r):[a-z]*? [a-z]+', 'foo bar',
          partial=True).span(), (0, 7))

        # Hg issue 291: Include Script Extensions as a supported Unicode property
        self.assertEqual(bool(regex.match(r'(?u)\p{Script:Beng}',
          '\u09EF')), True)
        self.assertEqual(bool(regex.match(r'(?u)\p{Script:Bengali}',
          '\u09EF')), True)
        self.assertEqual(bool(regex.match(r'(?u)\p{Script_Extensions:Bengali}',
          '\u09EF')), True)
        self.assertEqual(bool(regex.match(r'(?u)\p{Script_Extensions:Beng}',
          '\u09EF')), True)
        self.assertEqual(bool(regex.match(r'(?u)\p{Script_Extensions:Cakm}',
          '\u09EF')), True)
        self.assertEqual(bool(regex.match(r'(?u)\p{Script_Extensions:Sylo}',
          '\u09EF')), True)

        # Hg issue #293: scx (Script Extensions) property currently matches
        # incorrectly
        self.assertEqual(bool(regex.match(r'(?u)\p{scx:Latin}', 'P')), True)
        self.assertEqual(bool(regex.match(r'(?u)\p{scx:Ahom}', 'P')), False)
        self.assertEqual(bool(regex.match(r'(?u)\p{scx:Common}', '4')), True)
        self.assertEqual(bool(regex.match(r'(?u)\p{scx:Caucasian_Albanian}', '4')),
          False)
        self.assertEqual(bool(regex.match(r'(?u)\p{scx:Arabic}', '\u062A')), True)
        self.assertEqual(bool(regex.match(r'(?u)\p{scx:Balinese}', '\u062A')),
          False)
        self.assertEqual(bool(regex.match(r'(?u)\p{scx:Devanagari}', '\u091C')),
          True)
        self.assertEqual(bool(regex.match(r'(?u)\p{scx:Batak}', '\u091C')), False)

        # Hg issue 296: Group references are not taken into account when group is reporting the last match
        self.assertEqual(regex.fullmatch('(?P<x>.)*(?&x)', 'abc').captures('x'),
          ['a', 'b', 'c'])
        self.assertEqual(regex.fullmatch('(?P<x>.)*(?&x)', 'abc').group('x'),
          'b')

        self.assertEqual(regex.fullmatch('(?P<x>.)(?P<x>.)(?P<x>.)',
          'abc').captures('x'), ['a', 'b', 'c'])
        self.assertEqual(regex.fullmatch('(?P<x>.)(?P<x>.)(?P<x>.)',
          'abc').group('x'), 'c')

        # Hg issue 299: Partial gives misleading results with "open ended" regexp
        self.assertEqual(regex.match('(?:ab)*', 'ab', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?:ab)*', 'abab', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?:ab)*?', '', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?:ab)*+', 'ab', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?:ab)*+', 'abab', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?:ab)+', 'ab', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?:ab)+', 'abab', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?:ab)+?', 'ab', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?:ab)++', 'ab', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?:ab)++', 'abab', partial=True).partial,
          False)

        self.assertEqual(regex.match('(?r)(?:ab)*', 'ab', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?r)(?:ab)*', 'abab', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?r)(?:ab)*?', '', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?r)(?:ab)*+', 'ab', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?r)(?:ab)*+', 'abab', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?r)(?:ab)+', 'ab', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?r)(?:ab)+', 'abab', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?r)(?:ab)+?', 'ab', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?r)(?:ab)++', 'ab', partial=True).partial,
          False)
        self.assertEqual(regex.match('(?r)(?:ab)++', 'abab', partial=True).partial,
          False)

        self.assertEqual(regex.match('a*', '', partial=True).partial, False)
        self.assertEqual(regex.match('a*?', '', partial=True).partial, False)
        self.assertEqual(regex.match('a*+', '', partial=True).partial, False)
        self.assertEqual(regex.match('a+', '', partial=True).partial, True)
        self.assertEqual(regex.match('a+?', '', partial=True).partial, True)
        self.assertEqual(regex.match('a++', '', partial=True).partial, True)
        self.assertEqual(regex.match('a+', 'a', partial=True).partial, False)
        self.assertEqual(regex.match('a+?', 'a', partial=True).partial, False)
        self.assertEqual(regex.match('a++', 'a', partial=True).partial, False)

        self.assertEqual(regex.match('(?r)a*', '', partial=True).partial, False)
        self.assertEqual(regex.match('(?r)a*?', '', partial=True).partial, False)
        self.assertEqual(regex.match('(?r)a*+', '', partial=True).partial, False)
        self.assertEqual(regex.match('(?r)a+', '', partial=True).partial, True)
        self.assertEqual(regex.match('(?r)a+?', '', partial=True).partial, True)
        self.assertEqual(regex.match('(?r)a++', '', partial=True).partial, True)
        self.assertEqual(regex.match('(?r)a+', 'a', partial=True).partial, False)
        self.assertEqual(regex.match('(?r)a+?', 'a', partial=True).partial, False)
        self.assertEqual(regex.match('(?r)a++', 'a', partial=True).partial, False)

        self.assertEqual(regex.match(r"(?:\s*\w+'*)+", 'whatever', partial=True).partial,
          False)

        # Hg issue 300: segmentation fault
        pattern = ('(?P<termini5>GGCGTCACACTTTGCTATGCCATAGCAT[AG]TTTATCCATAAGA'
          'TTAGCGGATCCTACCTGACGCTTTTTATCGCAACTCTCTACTGTTTCTCCATAACAGAACATATTGA'
          'CTATCCGGTATTACCCGGCATGACAGGAGTAAAA){e<=1}'
          '(?P<gene>[ACGT]{1059}){e<=2}'
          '(?P<spacer>TAATCGTCTTGTTTGATACACAAGGGTCGCATCTGCGGCCCTTTTGCTTTTTTAAG'
          'TTGTAAGGATATGCCATTCTAGA){e<=0}'
          '(?P<barcode>[ACGT]{18}){e<=0}'
          '(?P<termini3>AGATCGG[CT]AGAGCGTCGTGTAGGGAAAGAGTGTGG){e<=1}')

        text = ('GCACGGCGTCACACTTTGCTATGCCATAGCATATTTATCCATAAGATTAGCGGATCCTACC'
          'TGACGCTTTTTATCGCAACTCTCTACTGTTTCTCCATAACAGAACATATTGACTATCCGGTATTACC'
          'CGGCATGACAGGAGTAAAAATGGCTATCGACGAAAACAAACAGAAAGCGTTGGCGGCAGCACTGGGC'
          'CAGATTGAGAAACAATTTGGTAAAGGCTCCATCATGCGCCTGGGTGAAGACCGTTCCATGGATGTGG'
          'AAACCATCTCTACCGGTTCGCTTTCACTGGATATCGCGCTTGGGGCAGGTGGTCTGCCGATGGGCCG'
          'TATCGTCGAAATCTACGGACCGGAATCTTCCGGTAAAACCACGCTGACGCTGCAGGTGATCGCCGCA'
          'GCGCAGCGTGAAGGTAAAACCTGTGCGTTTATCGATGCTGAACACGCGCTGGACCCAATCTACGCAC'
          'GTAAACTGGGCGTCGATATCGACAACCTGCTGTGCTCCCAGCCGGACACCGGCGAGCAGGCACTGGA'
          'AATCTGTGACGCCCTGGCGCGTTCTGGCGCAGTAGACGTTATCGTCGTTGACTCCGTGGCGGCACTG'
          'ACGCCGAAAGCGGAAATCGAAGGCGAAATCGGCGACTCTCATATGGGCCTTGCGGCACGTATGATGA'
          'GCCAGGCGATGCGTAAGCTGGCGGGTAACCTGAAGCAGTCCAACACGCTGCTGATCTTCATCAACCC'
          'CATCCGTATGAAAATTGGTGTGATGTTCGGCAACCCGGAAACCACTTACCGGTGGTAACGCGCTGAA'
          'ATTCTACGCCTCTGTTCGTCTCGACATCCGTTAAATCGGCGCGGTGAAAGAGGGCGAAAACGTGGTG'
          'GGTAGCGAAACCCGCGTGAAAGTGGTGAAGAACAAAATCGCTGCGCCGTTTAAACAGGCTGAATTCC'
          'AGATCCTCTACGGCGAAGGTATCAACTTCTACCCCGAACTGGTTGACCTGGGCGTAAAAGAGAAGCT'
          'GATCGAGAAAGCAGGCGCGTGGTACAGCTACAAAGGTGAGAAGATCGGTCAGGGTAAAGCGAATGCG'
          'ACTGCCTGGCTGAAATTTAACCCGGAAACCGCGAAAGAGATCGAGTGAAAAGTACGTGAGTTGCTGC'
          'TGAGCAACCCGAACTCAACGCCGGATTTCTCTGTAGATGATAGCGAAGGCGTAGCAGAAACTAACGA'
          'AGATTTTTAATCGTCTTGTTTGATACACAAGGGTCGCATCTGCGGCCCTTTTGCTTTTTTAAGTTGT'
          'AAGGATATGCCATTCTAGACAGTTAACACACCAACAAAGATCGGTAGAGCGTCGTGTAGGGAAAGAG'
          'TGTGGTACC')

        m = regex.search(pattern, text, flags=regex.BESTMATCH)
        self.assertEqual(m.fuzzy_counts, (0, 1, 0))
        self.assertEqual(m.fuzzy_changes, ([], [1206], []))

        # Hg issue 306: Fuzzy match parameters not respecting quantifier scope
        self.assertEqual(regex.search(r'(?e)(dogf(((oo){e<1})|((00){e<1}))d){e<2}',
          'dogfood').fuzzy_counts, (0, 0, 0))
        self.assertEqual(regex.search(r'(?e)(dogf(((oo){e<1})|((00){e<1}))d){e<2}',
          'dogfoot').fuzzy_counts, (1, 0, 0))

        # Hg issue 312: \X not matching graphemes with zero-width-joins
        self.assertEqual(regex.findall(r'\X',
          '\U0001F468\u200D\U0001F469\u200D\U0001F467\u200D\U0001F466'),
          ['\U0001F468\u200D\U0001F469\u200D\U0001F467\u200D\U0001F466'])

        # Hg issue 320: Abnormal performance
        self.assertEqual(bool(regex.search(r'(?=a)a', 'a')), True)
        self.assertEqual(bool(regex.search(r'(?!b)a', 'a')), True)

        # Hg issue 327: .fullmatch() causes MemoryError
        self.assertEqual(regex.fullmatch(r'((\d)*?)*?', '123').span(), (0, 3))

        # Hg issue 329: Wrong group matches when question mark quantifier is used within a look behind
        self.assertEqual(regex.search(r'''(?(DEFINE)(?<mydef>(?<wrong>THIS_SHOULD_NOT_MATCHx?)|(?<right>right))).*(?<=(?&mydef).*)''',
          'x right').capturesdict(), {'mydef': ['right'], 'wrong': [], 'right':
          ['right']})

        # Hg issue 338: specifying allowed characters when fuzzy-matching
        self.assertEqual(bool(regex.match(r'(?:cat){e<=1:[u]}', 'cut')), True)
        self.assertEqual(bool(regex.match(r'(?:cat){e<=1:u}', 'cut')), True)

        # Hg issue 353: fuzzy changes negative indexes
        self.assertEqual(regex.search(r'(?be)(AGTGTTCCCCGCGCCAGCGGGGATAAACCG){s<=5,i<=5,d<=5,s+i+d<=10}',
          'TTCCCCGCGCCAGCGGGGATAAACCG').fuzzy_changes, ([], [], [0, 1, 3, 5]))

        # Git issue 364: Contradictory values in fuzzy_counts and fuzzy_changes
        self.assertEqual(regex.match(r'(?:bc){e}', 'c').fuzzy_counts, (1, 0,
          1))
        self.assertEqual(regex.match(r'(?:bc){e}', 'c').fuzzy_changes, ([0],
          [], [1]))
        self.assertEqual(regex.match(r'(?e)(?:bc){e}', 'c').fuzzy_counts, (0,
          0, 1))
        self.assertEqual(regex.match(r'(?e)(?:bc){e}', 'c').fuzzy_changes,
          ([], [], [0]))
        self.assertEqual(regex.match(r'(?b)(?:bc){e}', 'c').fuzzy_counts, (0,
          0, 1))
        self.assertEqual(regex.match(r'(?b)(?:bc){e}', 'c').fuzzy_changes,
          ([], [], [0]))

        # Git issue 370: Confusions about Fuzzy matching behavior
        self.assertEqual(regex.match('(?e)(?:^(\\$ )?\\d{1,3}(,\\d{3})*(\\.\\d{2})$){e}',
          '$ 10,112.111.12').fuzzy_counts, (6, 0, 5))
        self.assertEqual(regex.match('(?e)(?:^(\\$ )?\\d{1,3}(,\\d{3})*(\\.\\d{2})$){s<=1}',
          '$ 10,112.111.12').fuzzy_counts, (1, 0, 0))
        self.assertEqual(regex.match('(?e)(?:^(\\$ )?\\d{1,3}(,\\d{3})*(\\.\\d{2})$){s<=1,i<=1,d<=1}',
          '$ 10,112.111.12').fuzzy_counts, (1, 0, 0))
        self.assertEqual(regex.match('(?e)(?:^(\\$ )?\\d{1,3}(,\\d{3})*(\\.\\d{2})$){s<=3}',
          '$ 10,1a2.111.12').fuzzy_counts, (2, 0, 0))
        self.assertEqual(regex.match('(?e)(?:^(\\$ )?\\d{1,3}(,\\d{3})*(\\.\\d{2})$){s<=2}',
          '$ 10,1a2.111.12').fuzzy_counts, (2, 0, 0))

        self.assertEqual(regex.fullmatch(r'(?e)(?:0?,0(?:,0)?){s<=1,d<=1}',
          ',0;0').fuzzy_counts, (1, 0, 0))
        self.assertEqual(regex.fullmatch(r'(?e)(?:0??,0(?:,0)?){s<=1,d<=1}',
          ',0;0').fuzzy_counts, (1, 0, 0))

        # Git issue 371: Specifying character set when fuzzy-matching allows characters not in the set
        self.assertEqual(regex.search(r"\b(?e)(?:\d{6,20}){i<=5:[\-\\\/]}\b",
          "cat dog starting at 00:01132.000. hello world"), None)

        # Git issue 385: Comments in expressions
        self.assertEqual(bool(regex.compile('(?#)')), True)
        self.assertEqual(bool(regex.compile('(?x)(?#)')), True)

        # Git issue 394: Unexpected behaviour in fuzzy matching with limited character set with IGNORECASE flag
        self.assertEqual(regex.findall(r'(\d+){i<=2:[ab]}', '123X4Y5'),
          ['123', '4', '5'])
        self.assertEqual(regex.findall(r'(?i)(\d+){i<=2:[ab]}', '123X4Y5'),
          ['123', '4', '5'])

        # Git issue 403: Fuzzy matching with wrong distance (unnecessary substitutions)
        self.assertEqual(regex.match(r'^(test){e<=5}$', 'terstin',
          flags=regex.B).fuzzy_counts, (0, 3, 0))

        # Git issue 408: regex fails with a quantified backreference but succeeds with repeated backref
        self.assertEqual(bool(regex.match(r"(?:(x*)\1\1\1)*x$", "x" * 5)), True)
        self.assertEqual(bool(regex.match(r"(?:(x*)\1{3})*x$", "x" * 5)), True)

        # Git issue 415: Fuzzy character restrictions don't apply to insertions at "right edge"
        self.assertEqual(regex.match(r't(?:es){s<=1:\d}t', 'te5t').group(),
          'te5t')
        self.assertEqual(regex.match(r't(?:es){s<=1:\d}t', 'tezt'), None)
        self.assertEqual(regex.match(r't(?:es){i<=1:\d}t', 'tes5t').group(),
          'tes5t')
        self.assertEqual(regex.match(r't(?:es){i<=1:\d}t', 'teszt'), None)
        self.assertEqual(regex.match(r't(?:es){i<=1:\d}t',
          'tes5t').fuzzy_changes, ([], [3], []))
        self.assertEqual(regex.match(r't(es){i<=1,0<e<=1}t', 'tes5t').group(),
          'tes5t')
        self.assertEqual(regex.match(r't(?:es){i<=1,0<e<=1:\d}t',
          'tes5t').fuzzy_changes, ([], [3], []))

        # Git issue 421: Fatal Python error: Segmentation fault
        self.assertEqual(regex.compile(r"(\d+ week|\d+ days)").split("7 days"), ['', '7 days', ''])
        self.assertEqual(regex.compile(r"(\d+ week|\d+ days)").split("10 days"), ['', '10 days', ''])

        self.assertEqual(regex.compile(r"[ ]* Name[ ]*\* ").search("  Name *"), None)

        self.assertEqual(regex.compile('a|\\.*pb\\.py').search('.geojs'), None)

        p = regex.compile('(?<=(?:\\A|\\W|_))(\\d+ decades? ago|\\d+ minutes ago|\\d+ seconds ago|in \\d+ decades?|\\d+ months ago|in \\d+ minutes|\\d+ minute ago|in \\d+ seconds|\\d+ second ago|\\d+ years ago|in \\d+ months|\\d+ month ago|\\d+ weeks ago|\\d+ hours ago|in \\d+ minute|in \\d+ second|in \\d+ years|\\d+ year ago|in \\d+ month|in \\d+ weeks|\\d+ week ago|\\d+ days ago|in \\d+ hours|\\d+ hour ago|in \\d+ year|in \\d+ week|in \\d+ days|\\d+ day ago|in \\d+ hour|\\d+ min ago|\\d+ sec ago|\\d+ yr ago|\\d+ mo ago|\\d+ wk ago|in \\d+ day|\\d+ hr ago|in \\d+ min|in \\d+ sec|in \\d+ yr|in \\d+ mo|in \\d+ wk|in \\d+ hr)(?=(?:\\Z|\\W|_))', flags=regex.I | regex.V0)
        self.assertEqual(p.search('1 month ago').group(), '1 month ago')
        self.assertEqual(p.search('9 hours 1 minute ago').group(), '1 minute ago')
        self.assertEqual(p.search('10 months 1 hour ago').group(), '1 hour ago')
        self.assertEqual(p.search('1 month 10 hours ago').group(), '10 hours ago')

        # Git issue 427: Possible bug with BESTMATCH
        sequence = 'TTCAGACGTGTGCTCTTCCGATCTCAATACCGACTCCTCACTGTGTGTCT'
        pattern = r'(?P<insert>.*)(?P<anchor>CTTCC){e<=1}(?P<umi>([ACGT]){4,6})(?P<sid>CAATACCGACTCCTCACTGTGT){e<=2}(?P<end>([ACGT]){0,6}$)'

        m = regex.match(pattern, sequence, flags=regex.BESTMATCH)
        self.assertEqual(m.span(), (0, 50))
        self.assertEqual(m.groupdict(), {'insert': 'TTCAGACGTGTGCT', 'anchor': 'CTTCC', 'umi': 'GATCT', 'sid': 'CAATACCGACTCCTCACTGTGT', 'end': 'GTCT'})

        m = regex.match(pattern, sequence, flags=regex.ENHANCEMATCH)
        self.assertEqual(m.span(), (0, 50))
        self.assertEqual(m.groupdict(), {'insert': 'TTCAGACGTGTGCT', 'anchor': 'CTTCC', 'umi': 'GATCT', 'sid': 'CAATACCGACTCCTCACTGTGT', 'end': 'GTCT'})

        # Git issue 433: Disagreement between fuzzy_counts and fuzzy_changes
        pattern = r'(?P<insert>.*)(?P<anchor>AACACTGG){e<=1}(?P<umi>([AT][CG]){5}){e<=2}(?P<sid>GTAACCGAAG){e<=2}(?P<end>([ACGT]){0,6}$)'

        sequence = 'GGAAAACACTGGTCTCAGTCTCGTAACCGAAGTGGTCG'
        m = regex.match(pattern, sequence, flags=regex.BESTMATCH)
        self.assertEqual(m.fuzzy_counts, (0, 0, 0))
        self.assertEqual(m.fuzzy_changes, ([], [], []))

        sequence = 'GGAAAACACTGGTCTCAGTCTCGTCCCCGAAGTGGTCG'
        m = regex.match(pattern, sequence, flags=regex.BESTMATCH)
        self.assertEqual(m.fuzzy_counts, (2, 0, 0))
        self.assertEqual(m.fuzzy_changes, ([24, 25], [], []))

        # Git issue 439: Unmatched groups: sub vs subf
        self.assertEqual(regex.sub(r'(test1)|(test2)', r'matched: \1\2', 'test1'), 'matched: test1')
        self.assertEqual(regex.subf(r'(test1)|(test2)', r'matched: {1}{2}', 'test1'), 'matched: test1')
        self.assertEqual(regex.search(r'(test1)|(test2)', 'matched: test1').expand(r'matched: \1\2'), 'matched: test1'),
        self.assertEqual(regex.search(r'(test1)|(test2)', 'matched: test1').expandf(r'matched: {1}{2}'), 'matched: test1')

        # Git issue 442: Fuzzy regex matching doesn't seem to test insertions correctly
        self.assertEqual(regex.search(r"(?:\bha\b){i:[ ]}", "having"), None)
        self.assertEqual(regex.search(r"(?:\bha\b){i:[ ]}", "having", flags=regex.I), None)

        # Git issue 467: Scoped inline flags 'a', 'u' and 'L' affect global flags
        self.assertEqual(regex.match(r'(?a:\w)\w', 'd\N{CYRILLIC SMALL LETTER ZHE}').span(), (0, 2))
        self.assertEqual(regex.match(r'(?a:\w)(?u:\w)', 'd\N{CYRILLIC SMALL LETTER ZHE}').span(), (0, 2))

        # Git issue 473: Emoji classified as letter
        self.assertEqual(regex.match(r'^\p{LC}+$', '\N{SMILING CAT FACE WITH OPEN MOUTH}'), None)
        self.assertEqual(regex.match(r'^\p{So}+$', '\N{SMILING CAT FACE WITH OPEN MOUTH}').span(), (0, 1))

        # Git issue 474: regex has no equivalent to `re.Match.groups()` for captures
        self.assertEqual(regex.match(r'(.)+', 'abc').allcaptures(), (['abc'], ['a', 'b', 'c']))
        self.assertEqual(regex.match(r'(.)+', 'abc').allspans(), ([(0, 3)], [(0, 1), (1, 2), (2, 3)]))

        # Git issue 477: \v for vertical spacing
        self.assertEqual(bool(regex.fullmatch(r'\p{HorizSpace}+', '\t \xA0\u1680\u180E\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200A\u202F\u205F\u3000')), True)
        self.assertEqual(bool(regex.fullmatch(r'\p{VertSpace}+', '\n\v\f\r\x85\u2028\u2029')), True)

        # Git issue 479: Segmentation fault when using conditional pattern
        self.assertEqual(regex.match(r'(?(?<=A)|(?(?![^B])C|D))', 'A'), None)
        self.assertEqual(regex.search(r'(?(?<=A)|(?(?![^B])C|D))', 'A').span(), (1, 1))

        # Git issue 494: Backtracking failure matching regex ^a?(a?)b?c\1$ against string abca
        self.assertEqual(regex.search(r"^a?(a?)b?c\1$", "abca").span(), (0, 4))

        # Git issue 498: Conditional negative lookahead inside positive lookahead fails to match
        self.assertEqual(regex.match(r'(?(?=a).|..)', 'ab').span(), (0, 1))
        self.assertEqual(regex.match(r'(?(?=b).|..)', 'ab').span(), (0, 2))
        self.assertEqual(regex.match(r'(?(?!a).|..)', 'ab').span(), (0, 2))
        self.assertEqual(regex.match(r'(?(?!b).|..)', 'ab').span(), (0, 1))

    def test_fuzzy_ext(self):
        self.assertEqual(bool(regex.fullmatch(r'(?r)(?:a){e<=1:[a-z]}', 'e')),
          True)
        self.assertEqual(bool(regex.fullmatch(r'(?:a){e<=1:[a-z]}', 'e')),
          True)
        self.assertEqual(bool(regex.fullmatch(r'(?:a){e<=1:[a-z]}', '-')),
          False)
        self.assertEqual(bool(regex.fullmatch(r'(?r)(?:a){e<=1:[a-z]}', '-')),
          False)

        self.assertEqual(bool(regex.fullmatch(r'(?:a){e<=1:[a-z]}', 'ae')),
          True)
        self.assertEqual(bool(regex.fullmatch(r'(?r)(?:a){e<=1:[a-z]}',
          'ae')), True)
        self.assertEqual(bool(regex.fullmatch(r'(?:a){e<=1:[a-z]}', 'a-')),
          False)
        self.assertEqual(bool(regex.fullmatch(r'(?r)(?:a){e<=1:[a-z]}',
          'a-')), False)

        self.assertEqual(bool(regex.fullmatch(r'(?:ab){e<=1:[a-z]}', 'ae')),
           True)
        self.assertEqual(bool(regex.fullmatch(r'(?r)(?:ab){e<=1:[a-z]}',
           'ae')), True)
        self.assertEqual(bool(regex.fullmatch(r'(?:ab){e<=1:[a-z]}', 'a-')),
           False)
        self.assertEqual(bool(regex.fullmatch(r'(?r)(?:ab){e<=1:[a-z]}',
           'a-')), False)

        self.assertEqual(bool(regex.fullmatch(r'(a)\1{e<=1:[a-z]}', 'ae')),
           True)
        self.assertEqual(bool(regex.fullmatch(r'(?r)\1{e<=1:[a-z]}(a)',
           'ea')), True)
        self.assertEqual(bool(regex.fullmatch(r'(a)\1{e<=1:[a-z]}', 'a-')),
           False)
        self.assertEqual(bool(regex.fullmatch(r'(?r)\1{e<=1:[a-z]}(a)',
           '-a')), False)

        self.assertEqual(bool(regex.fullmatch(r'(?fiu)(?:\N{LATIN SMALL LETTER SHARP S}){e<=1:[a-z]}',
          'ts')), True)
        self.assertEqual(bool(regex.fullmatch(r'(?fiu)(?:\N{LATIN SMALL LETTER SHARP S}){e<=1:[a-z]}',
          'st')), True)
        self.assertEqual(bool(regex.fullmatch(r'(?firu)(?:\N{LATIN SMALL LETTER SHARP S}){e<=1:[a-z]}',
          'st')), True)
        self.assertEqual(bool(regex.fullmatch(r'(?firu)(?:\N{LATIN SMALL LETTER SHARP S}){e<=1:[a-z]}',
          'ts')), True)
        self.assertEqual(bool(regex.fullmatch(r'(?fiu)(?:\N{LATIN SMALL LETTER SHARP S}){e<=1:[a-z]}',
          '-s')), False)
        self.assertEqual(bool(regex.fullmatch(r'(?fiu)(?:\N{LATIN SMALL LETTER SHARP S}){e<=1:[a-z]}',
          's-')), False)
        self.assertEqual(bool(regex.fullmatch(r'(?firu)(?:\N{LATIN SMALL LETTER SHARP S}){e<=1:[a-z]}',
          's-')), False)
        self.assertEqual(bool(regex.fullmatch(r'(?firu)(?:\N{LATIN SMALL LETTER SHARP S}){e<=1:[a-z]}',
          '-s')), False)

        self.assertEqual(bool(regex.fullmatch(r'(?fiu)(\N{LATIN SMALL LETTER SHARP S})\1{e<=1:[a-z]}',
           'ssst')), True)
        self.assertEqual(bool(regex.fullmatch(r'(?fiu)(\N{LATIN SMALL LETTER SHARP S})\1{e<=1:[a-z]}',
           'ssts')), True)
        self.assertEqual(bool(regex.fullmatch(r'(?firu)\1{e<=1:[a-z]}(\N{LATIN SMALL LETTER SHARP S})',
           'stss')), True)
        self.assertEqual(bool(regex.fullmatch(r'(?firu)\1{e<=1:[a-z]}(\N{LATIN SMALL LETTER SHARP S})',
           'tsss')), True)
        self.assertEqual(bool(regex.fullmatch(r'(?fiu)(\N{LATIN SMALL LETTER SHARP S})\1{e<=1:[a-z]}',
           'ss-s')), False)
        self.assertEqual(bool(regex.fullmatch(r'(?fiu)(\N{LATIN SMALL LETTER SHARP S})\1{e<=1:[a-z]}',
           'sss-')), False)
        self.assertEqual(bool(regex.fullmatch(r'(?firu)(\N{LATIN SMALL LETTER SHARP S})\1{e<=1:[a-z]}',
           '-s')), False)
        self.assertEqual(bool(regex.fullmatch(r'(?firu)(\N{LATIN SMALL LETTER SHARP S})\1{e<=1:[a-z]}',
           's-')), False)

        self.assertEqual(bool(regex.fullmatch(r'(?fiu)(ss)\1{e<=1:[a-z]}',
           '\N{LATIN SMALL LETTER SHARP S}ts')), True)
        self.assertEqual(bool(regex.fullmatch(r'(?fiu)(ss)\1{e<=1:[a-z]}',
           '\N{LATIN SMALL LETTER SHARP S}st')), True)
        self.assertEqual(bool(regex.fullmatch(r'(?firu)\1{e<=1:[a-z]}(ss)',
           'st\N{LATIN SMALL LETTER SHARP S}')), True)
        self.assertEqual(bool(regex.fullmatch(r'(?firu)\1{e<=1:[a-z]}(ss)',
           'ts\N{LATIN SMALL LETTER SHARP S}')), True)
        self.assertEqual(bool(regex.fullmatch(r'(?fiu)(ss)\1{e<=1:[a-z]}',
           '\N{LATIN SMALL LETTER SHARP S}-s')), False)
        self.assertEqual(bool(regex.fullmatch(r'(?fiu)(ss)\1{e<=1:[a-z]}',
           '\N{LATIN SMALL LETTER SHARP S}s-')), False)
        self.assertEqual(bool(regex.fullmatch(r'(?firu)(ss)\1{e<=1:[a-z]}',
           's-\N{LATIN SMALL LETTER SHARP S}')), False)
        self.assertEqual(bool(regex.fullmatch(r'(?firu)(ss)\1{e<=1:[a-z]}',
           '-s\N{LATIN SMALL LETTER SHARP S}')), False)

    def test_subscripted_captures(self):
        self.assertEqual(regex.match(r'(?P<x>.)+',
          'abc').expandf('{0} {0[0]} {0[-1]}'), 'abc abc abc')
        self.assertEqual(regex.match(r'(?P<x>.)+',
          'abc').expandf('{1} {1[0]} {1[1]} {1[2]} {1[-1]} {1[-2]} {1[-3]}'),
          'c a b c c b a')
        self.assertEqual(regex.match(r'(?P<x>.)+',
          'abc').expandf('{x} {x[0]} {x[1]} {x[2]} {x[-1]} {x[-2]} {x[-3]}'),
          'c a b c c b a')

        self.assertEqual(regex.subf(r'(?P<x>.)+', r'{0} {0[0]} {0[-1]}',
          'abc'), 'abc abc abc')
        self.assertEqual(regex.subf(r'(?P<x>.)+',
          '{1} {1[0]} {1[1]} {1[2]} {1[-1]} {1[-2]} {1[-3]}', 'abc'),
          'c a b c c b a')
        self.assertEqual(regex.subf(r'(?P<x>.)+',
          '{x} {x[0]} {x[1]} {x[2]} {x[-1]} {x[-2]} {x[-3]}', 'abc'),
          'c a b c c b a')

    def test_more_zerowidth(self):
        if sys.version_info >= (3, 7, 0):
            self.assertEqual(regex.split(r'\b|:+', 'a::bc'), ['', 'a', '', '',
              'bc', ''])
            self.assertEqual(regex.sub(r'\b|:+', '-', 'a::bc'), '-a---bc-')
            self.assertEqual(regex.findall(r'\b|:+', 'a::bc'), ['', '', '::',
              '', ''])
            self.assertEqual([m.span() for m in regex.finditer(r'\b|:+',
              'a::bc')], [(0, 0), (1, 1), (1, 3), (3, 3), (5, 5)])
            self.assertEqual([m.span() for m in regex.finditer(r'(?m)^\s*?$',
              'foo\n\n\nbar')], [(4, 4), (4, 5), (5, 5)])

    def test_line_ending(self):
      self.assertEqual(regex.findall(r'\R', '\r\n\n\x0B\f\r\x85\u2028\u2029'),
        ['\r\n', '\n', '\x0B', '\f', '\r', '\x85', '\u2028', '\u2029'])
      self.assertEqual(regex.findall(br'\R', b'\r\n\n\x0B\f\r\x85'), [b'\r\n',
        b'\n', b'\x0B', b'\f', b'\r'])

def test_main():
    unittest.main(verbosity=2)

if __name__ == "__main__":
    test_main()
