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authorS. Solomon Darnell2025-03-28 21:52:21 -0500
committerS. Solomon Darnell2025-03-28 21:52:21 -0500
commit4a52a71956a8d46fcb7294ac71734504bb09bcc2 (patch)
treeee3dc5af3b6313e921cd920906356f5d4febc4ed /.venv/lib/python3.12/site-packages/regex/test_regex.py
parentcc961e04ba734dd72309fb548a2f97d67d578813 (diff)
downloadgn-ai-master.tar.gz
two version of R2R are here HEAD master
Diffstat (limited to '.venv/lib/python3.12/site-packages/regex/test_regex.py')
-rw-r--r--.venv/lib/python3.12/site-packages/regex/test_regex.py4488
1 files changed, 4488 insertions, 0 deletions
diff --git a/.venv/lib/python3.12/site-packages/regex/test_regex.py b/.venv/lib/python3.12/site-packages/regex/test_regex.py
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+++ b/.venv/lib/python3.12/site-packages/regex/test_regex.py
@@ -0,0 +1,4488 @@
+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))
+
+        # Git issue 525: segfault when fuzzy matching empty list
+        self.assertEqual(regex.match(r"(\L<foo>){e<=5}", "blah", foo=[]).span(), (0, 0))
+
+        # Git issue 527: `VERBOSE`/`X` flag breaks `\N` escapes
+        self.assertEqual(regex.compile(r'\N{LATIN SMALL LETTER A}').match('a').span(), (0, 1))
+        self.assertEqual(regex.compile(r'\N{LATIN SMALL LETTER A}', flags=regex.X).match('a').span(), (0, 1))
+
+        # Git issue 539: Bug: Partial matching fails on a simple example
+        self.assertEqual(regex.match(r"[^/]*b/ccc", "b/ccc", partial=True).span(), (0, 5))
+        self.assertEqual(regex.match(r"[^/]*b/ccc", "b/ccb", partial=True), None)
+        self.assertEqual(regex.match(r"[^/]*b/ccc", "b/cc", partial=True).span(), (0, 4))
+        self.assertEqual(regex.match(r"[^/]*b/xyz", "b/xy", partial=True).span(), (0, 4))
+        self.assertEqual(regex.match(r"[^/]*b/xyz", "b/yz", partial=True), None)
+
+        self.assertEqual(regex.match(r"(?i)[^/]*b/ccc", "b/ccc", partial=True).span(), (0, 5))
+        self.assertEqual(regex.match(r"(?i)[^/]*b/ccc", "b/ccb", partial=True), None)
+        self.assertEqual(regex.match(r"(?i)[^/]*b/ccc", "b/cc", partial=True).span(), (0, 4))
+        self.assertEqual(regex.match(r"(?i)[^/]*b/xyz", "b/xy", partial=True).span(), (0, 4))
+        self.assertEqual(regex.match(r"(?i)[^/]*b/xyz", "b/yz", partial=True), None)
+
+        # Git issue 546: Partial match not working in some instances with non-greedy capture
+        self.assertEqual(bool(regex.match(r'<thinking>.*?</thinking>', '<', partial=True)), True)
+        self.assertEqual(bool(regex.match(r'<thinking>.*?</thinking>', '<thinking', partial=True)), True)
+        self.assertEqual(bool(regex.match(r'<thinking>.*?</thinking>', '<thinking>', partial=True)), True)
+        self.assertEqual(bool(regex.match(r'<thinking>.*?</thinking>', '<thinking>x', partial=True)), True)
+        self.assertEqual(bool(regex.match(r'<thinking>.*?</thinking>', '<thinking>xyz abc', partial=True)), True)
+        self.assertEqual(bool(regex.match(r'<thinking>.*?</thinking>', '<thinking>xyz abc foo', partial=True)), True)
+        self.assertEqual(bool(regex.match(r'<thinking>.*?</thinking>', '<thinking>xyz abc foo ', partial=True)), True)
+        self.assertEqual(bool(regex.match(r'<thinking>.*?</thinking>', '<thinking>xyz abc foo bar', partial=True)), True)
+
+    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()