diff --git a/Lib/encodings/aliases.py b/Lib/encodings/aliases.py
index d85afd6d5c..6a5ca046b5 100644
--- a/Lib/encodings/aliases.py
+++ b/Lib/encodings/aliases.py
@@ -209,6 +209,7 @@
     'ms932'              : 'cp932',
     'mskanji'            : 'cp932',
     'ms_kanji'           : 'cp932',
+    'windows_31j'        : 'cp932',
 
     # cp949 codec
     '949'                : 'cp949',
diff --git a/Lib/encodings/idna.py b/Lib/encodings/idna.py
index 5396047a7f..0c90b4c9fe 100644
--- a/Lib/encodings/idna.py
+++ b/Lib/encodings/idna.py
@@ -11,7 +11,7 @@
 sace_prefix = "xn--"
 
 # This assumes query strings, so AllowUnassigned is true
-def nameprep(label):
+def nameprep(label):  # type: (str) -> str
     # Map
     newlabel = []
     for c in label:
@@ -25,7 +25,7 @@ def nameprep(label):
     label = unicodedata.normalize("NFKC", label)
 
     # Prohibit
-    for c in label:
+    for i, c in enumerate(label):
         if stringprep.in_table_c12(c) or \
            stringprep.in_table_c22(c) or \
            stringprep.in_table_c3(c) or \
@@ -35,7 +35,7 @@ def nameprep(label):
            stringprep.in_table_c7(c) or \
            stringprep.in_table_c8(c) or \
            stringprep.in_table_c9(c):
-            raise UnicodeError("Invalid character %r" % c)
+            raise UnicodeEncodeError("idna", label, i, i+1, f"Invalid character {c!r}")
 
     # Check bidi
     RandAL = [stringprep.in_table_d1(x) for x in label]
@@ -46,29 +46,38 @@ def nameprep(label):
         # This is table C.8, which was already checked
         # 2) If a string contains any RandALCat character, the string
         # MUST NOT contain any LCat character.
-        if any(stringprep.in_table_d2(x) for x in label):
-            raise UnicodeError("Violation of BIDI requirement 2")
+        for i, x in enumerate(label):
+            if stringprep.in_table_d2(x):
+                raise UnicodeEncodeError("idna", label, i, i+1,
+                                         "Violation of BIDI requirement 2")
         # 3) If a string contains any RandALCat character, a
         # RandALCat character MUST be the first character of the
         # string, and a RandALCat character MUST be the last
         # character of the string.
-        if not RandAL[0] or not RandAL[-1]:
-            raise UnicodeError("Violation of BIDI requirement 3")
+        if not RandAL[0]:
+            raise UnicodeEncodeError("idna", label, 0, 1,
+                                     "Violation of BIDI requirement 3")
+        if not RandAL[-1]:
+            raise UnicodeEncodeError("idna", label, len(label)-1, len(label),
+                                     "Violation of BIDI requirement 3")
 
     return label
 
-def ToASCII(label):
+def ToASCII(label):  # type: (str) -> bytes
     try:
         # Step 1: try ASCII
-        label = label.encode("ascii")
-    except UnicodeError:
+        label_ascii = label.encode("ascii")
+    except UnicodeEncodeError:
         pass
     else:
         # Skip to step 3: UseSTD3ASCIIRules is false, so
         # Skip to step 8.
-        if 0 < len(label) < 64:
-            return label
-        raise UnicodeError("label empty or too long")
+        if 0 < len(label_ascii) < 64:
+            return label_ascii
+        if len(label) == 0:
+            raise UnicodeEncodeError("idna", label, 0, 1, "label empty")
+        else:
+            raise UnicodeEncodeError("idna", label, 0, len(label), "label too long")
 
     # Step 2: nameprep
     label = nameprep(label)
@@ -76,29 +85,34 @@ def ToASCII(label):
     # Step 3: UseSTD3ASCIIRules is false
     # Step 4: try ASCII
     try:
-        label = label.encode("ascii")
-    except UnicodeError:
+        label_ascii = label.encode("ascii")
+    except UnicodeEncodeError:
         pass
     else:
         # Skip to step 8.
         if 0 < len(label) < 64:
-            return label
-        raise UnicodeError("label empty or too long")
+            return label_ascii
+        if len(label) == 0:
+            raise UnicodeEncodeError("idna", label, 0, 1, "label empty")
+        else:
+            raise UnicodeEncodeError("idna", label, 0, len(label), "label too long")
 
     # Step 5: Check ACE prefix
-    if label.startswith(sace_prefix):
-        raise UnicodeError("Label starts with ACE prefix")
+    if label.lower().startswith(sace_prefix):
+        raise UnicodeEncodeError(
+            "idna", label, 0, len(sace_prefix), "Label starts with ACE prefix")
 
     # Step 6: Encode with PUNYCODE
-    label = label.encode("punycode")
+    label_ascii = label.encode("punycode")
 
     # Step 7: Prepend ACE prefix
-    label = ace_prefix + label
+    label_ascii = ace_prefix + label_ascii
 
     # Step 8: Check size
-    if 0 < len(label) < 64:
-        return label
-    raise UnicodeError("label empty or too long")
+    # do not check for empty as we prepend ace_prefix.
+    if len(label_ascii) < 64:
+        return label_ascii
+    raise UnicodeEncodeError("idna", label, 0, len(label), "label too long")
 
 def ToUnicode(label):
     if len(label) > 1024:
@@ -110,7 +124,9 @@ def ToUnicode(label):
         # per https://www.rfc-editor.org/rfc/rfc3454#section-3.1 while still
         # preventing us from wasting time decoding a big thing that'll just
         # hit the actual <= 63 length limit in Step 6.
-        raise UnicodeError("label way too long")
+        if isinstance(label, str):
+            label = label.encode("utf-8", errors="backslashreplace")
+        raise UnicodeDecodeError("idna", label, 0, len(label), "label way too long")
     # Step 1: Check for ASCII
     if isinstance(label, bytes):
         pure_ascii = True
@@ -118,25 +134,32 @@ def ToUnicode(label):
         try:
             label = label.encode("ascii")
             pure_ascii = True
-        except UnicodeError:
+        except UnicodeEncodeError:
             pure_ascii = False
     if not pure_ascii:
+        assert isinstance(label, str)
         # Step 2: Perform nameprep
         label = nameprep(label)
         # It doesn't say this, but apparently, it should be ASCII now
         try:
             label = label.encode("ascii")
-        except UnicodeError:
-            raise UnicodeError("Invalid character in IDN label")
+        except UnicodeEncodeError as exc:
+            raise UnicodeEncodeError("idna", label, exc.start, exc.end,
+                                     "Invalid character in IDN label")
     # Step 3: Check for ACE prefix
-    if not label.startswith(ace_prefix):
+    assert isinstance(label, bytes)
+    if not label.lower().startswith(ace_prefix):
         return str(label, "ascii")
 
     # Step 4: Remove ACE prefix
     label1 = label[len(ace_prefix):]
 
     # Step 5: Decode using PUNYCODE
-    result = label1.decode("punycode")
+    try:
+        result = label1.decode("punycode")
+    except UnicodeDecodeError as exc:
+        offset = len(ace_prefix)
+        raise UnicodeDecodeError("idna", label, offset+exc.start, offset+exc.end, exc.reason)
 
     # Step 6: Apply ToASCII
     label2 = ToASCII(result)
@@ -144,7 +167,8 @@ def ToUnicode(label):
     # Step 7: Compare the result of step 6 with the one of step 3
     # label2 will already be in lower case.
     if str(label, "ascii").lower() != str(label2, "ascii"):
-        raise UnicodeError("IDNA does not round-trip", label, label2)
+        raise UnicodeDecodeError("idna", label, 0, len(label),
+                                 f"IDNA does not round-trip, '{label!r}' != '{label2!r}'")
 
     # Step 8: return the result of step 5
     return result
@@ -156,7 +180,7 @@ def encode(self, input, errors='strict'):
 
         if errors != 'strict':
             # IDNA is quite clear that implementations must be strict
-            raise UnicodeError("unsupported error handling "+errors)
+            raise UnicodeError(f"Unsupported error handling: {errors}")
 
         if not input:
             return b'', 0
@@ -168,11 +192,16 @@ def encode(self, input, errors='strict'):
         else:
             # ASCII name: fast path
             labels = result.split(b'.')
-            for label in labels[:-1]:
-                if not (0 < len(label) < 64):
-                    raise UnicodeError("label empty or too long")
-            if len(labels[-1]) >= 64:
-                raise UnicodeError("label too long")
+            for i, label in enumerate(labels[:-1]):
+                if len(label) == 0:
+                    offset = sum(len(l) for l in labels[:i]) + i
+                    raise UnicodeEncodeError("idna", input, offset, offset+1,
+                                             "label empty")
+            for i, label in enumerate(labels):
+                if len(label) >= 64:
+                    offset = sum(len(l) for l in labels[:i]) + i
+                    raise UnicodeEncodeError("idna", input, offset, offset+len(label),
+                                             "label too long")
             return result, len(input)
 
         result = bytearray()
@@ -182,17 +211,27 @@ def encode(self, input, errors='strict'):
             del labels[-1]
         else:
             trailing_dot = b''
-        for label in labels:
+        for i, label in enumerate(labels):
             if result:
                 # Join with U+002E
                 result.extend(b'.')
-            result.extend(ToASCII(label))
+            try:
+                result.extend(ToASCII(label))
+            except (UnicodeEncodeError, UnicodeDecodeError) as exc:
+                offset = sum(len(l) for l in labels[:i]) + i
+                raise UnicodeEncodeError(
+                    "idna",
+                    input,
+                    offset + exc.start,
+                    offset + exc.end,
+                    exc.reason,
+                )
         return bytes(result+trailing_dot), len(input)
 
     def decode(self, input, errors='strict'):
 
         if errors != 'strict':
-            raise UnicodeError("Unsupported error handling "+errors)
+            raise UnicodeError(f"Unsupported error handling: {errors}")
 
         if not input:
             return "", 0
@@ -202,7 +241,7 @@ def decode(self, input, errors='strict'):
             # XXX obviously wrong, see #3232
             input = bytes(input)
 
-        if ace_prefix not in input:
+        if ace_prefix not in input.lower():
             # Fast path
             try:
                 return input.decode('ascii'), len(input)
@@ -218,8 +257,15 @@ def decode(self, input, errors='strict'):
             trailing_dot = ''
 
         result = []
-        for label in labels:
-            result.append(ToUnicode(label))
+        for i, label in enumerate(labels):
+            try:
+                u_label = ToUnicode(label)
+            except (UnicodeEncodeError, UnicodeDecodeError) as exc:
+                offset = sum(len(x) for x in labels[:i]) + len(labels[:i])
+                raise UnicodeDecodeError(
+                    "idna", input, offset+exc.start, offset+exc.end, exc.reason)
+            else:
+                result.append(u_label)
 
         return ".".join(result)+trailing_dot, len(input)
 
@@ -227,7 +273,7 @@ class IncrementalEncoder(codecs.BufferedIncrementalEncoder):
     def _buffer_encode(self, input, errors, final):
         if errors != 'strict':
             # IDNA is quite clear that implementations must be strict
-            raise UnicodeError("unsupported error handling "+errors)
+            raise UnicodeError(f"Unsupported error handling: {errors}")
 
         if not input:
             return (b'', 0)
@@ -251,7 +297,16 @@ def _buffer_encode(self, input, errors, final):
                 # Join with U+002E
                 result.extend(b'.')
                 size += 1
-            result.extend(ToASCII(label))
+            try:
+                result.extend(ToASCII(label))
+            except (UnicodeEncodeError, UnicodeDecodeError) as exc:
+                raise UnicodeEncodeError(
+                    "idna",
+                    input,
+                    size + exc.start,
+                    size + exc.end,
+                    exc.reason,
+                )
             size += len(label)
 
         result += trailing_dot
@@ -261,7 +316,7 @@ def _buffer_encode(self, input, errors, final):
 class IncrementalDecoder(codecs.BufferedIncrementalDecoder):
     def _buffer_decode(self, input, errors, final):
         if errors != 'strict':
-            raise UnicodeError("Unsupported error handling "+errors)
+            raise UnicodeError(f"Unsupported error handling: {errors}")
 
         if not input:
             return ("", 0)
@@ -271,7 +326,11 @@ def _buffer_decode(self, input, errors, final):
             labels = dots.split(input)
         else:
             # Must be ASCII string
-            input = str(input, "ascii")
+            try:
+                input = str(input, "ascii")
+            except (UnicodeEncodeError, UnicodeDecodeError) as exc:
+                raise UnicodeDecodeError("idna", input,
+                                         exc.start, exc.end, exc.reason)
             labels = input.split(".")
 
         trailing_dot = ''
@@ -288,7 +347,18 @@ def _buffer_decode(self, input, errors, final):
         result = []
         size = 0
         for label in labels:
-            result.append(ToUnicode(label))
+            try:
+                u_label = ToUnicode(label)
+            except (UnicodeEncodeError, UnicodeDecodeError) as exc:
+                raise UnicodeDecodeError(
+                    "idna",
+                    input.encode("ascii", errors="backslashreplace"),
+                    size + exc.start,
+                    size + exc.end,
+                    exc.reason,
+                )
+            else:
+                result.append(u_label)
             if size:
                 size += 1
             size += len(label)
diff --git a/Lib/encodings/palmos.py b/Lib/encodings/palmos.py
index c506d65452..df164ca5b9 100644
--- a/Lib/encodings/palmos.py
+++ b/Lib/encodings/palmos.py
@@ -201,7 +201,7 @@ def getregentry():
     '\u02dc'   #  0x98 -> SMALL TILDE
     '\u2122'   #  0x99 -> TRADE MARK SIGN
     '\u0161'   #  0x9A -> LATIN SMALL LETTER S WITH CARON
-    '\x9b'     #  0x9B -> <control>
+    '\u203a'   #  0x9B -> SINGLE RIGHT-POINTING ANGLE QUOTATION MARK
     '\u0153'   #  0x9C -> LATIN SMALL LIGATURE OE
     '\x9d'     #  0x9D -> <control>
     '\x9e'     #  0x9E -> <control>
diff --git a/Lib/encodings/punycode.py b/Lib/encodings/punycode.py
index 1c57264470..4622fc8c92 100644
--- a/Lib/encodings/punycode.py
+++ b/Lib/encodings/punycode.py
@@ -1,4 +1,4 @@
-""" Codec for the Punicode encoding, as specified in RFC 3492
+""" Codec for the Punycode encoding, as specified in RFC 3492
 
 Written by Martin v. Löwis.
 """
@@ -131,10 +131,11 @@ def decode_generalized_number(extended, extpos, bias, errors):
     j = 0
     while 1:
         try:
-            char = ord(extended[extpos])
+            char = extended[extpos]
         except IndexError:
             if errors == "strict":
-                raise UnicodeError("incomplete punicode string")
+                raise UnicodeDecodeError("punycode", extended, extpos, extpos+1,
+                                         "incomplete punycode string")
             return extpos + 1, None
         extpos += 1
         if 0x41 <= char <= 0x5A: # A-Z
@@ -142,8 +143,8 @@ def decode_generalized_number(extended, extpos, bias, errors):
         elif 0x30 <= char <= 0x39:
             digit = char - 22 # 0x30-26
         elif errors == "strict":
-            raise UnicodeError("Invalid extended code point '%s'"
-                               % extended[extpos-1])
+            raise UnicodeDecodeError("punycode", extended, extpos-1, extpos,
+                                     f"Invalid extended code point '{extended[extpos-1]}'")
         else:
             return extpos, None
         t = T(j, bias)
@@ -155,11 +156,14 @@ def decode_generalized_number(extended, extpos, bias, errors):
 
 
 def insertion_sort(base, extended, errors):
-    """3.2 Insertion unsort coding"""
+    """3.2 Insertion sort coding"""
+    # This function raises UnicodeDecodeError with position in the extended.
+    # Caller should add the offset.
     char = 0x80
     pos = -1
     bias = 72
     extpos = 0
+
     while extpos < len(extended):
         newpos, delta = decode_generalized_number(extended, extpos,
                                                   bias, errors)
@@ -171,7 +175,9 @@ def insertion_sort(base, extended, errors):
         char += pos // (len(base) + 1)
         if char > 0x10FFFF:
             if errors == "strict":
-                raise UnicodeError("Invalid character U+%x" % char)
+                raise UnicodeDecodeError(
+                    "punycode", extended, pos-1, pos,
+                    f"Invalid character U+{char:x}")
             char = ord('?')
         pos = pos % (len(base) + 1)
         base = base[:pos] + chr(char) + base[pos:]
@@ -187,11 +193,21 @@ def punycode_decode(text, errors):
     pos = text.rfind(b"-")
     if pos == -1:
         base = ""
-        extended = str(text, "ascii").upper()
+        extended = text.upper()
     else:
-        base = str(text[:pos], "ascii", errors)
-        extended = str(text[pos+1:], "ascii").upper()
-    return insertion_sort(base, extended, errors)
+        try:
+            base = str(text[:pos], "ascii", errors)
+        except UnicodeDecodeError as exc:
+            raise UnicodeDecodeError("ascii", text, exc.start, exc.end,
+                                     exc.reason) from None
+        extended = text[pos+1:].upper()
+    try:
+        return insertion_sort(base, extended, errors)
+    except UnicodeDecodeError as exc:
+        offset = pos + 1
+        raise UnicodeDecodeError("punycode", text,
+                                 offset+exc.start, offset+exc.end,
+                                 exc.reason) from None
 
 ### Codec APIs
 
@@ -203,7 +219,7 @@ def encode(self, input, errors='strict'):
 
     def decode(self, input, errors='strict'):
         if errors not in ('strict', 'replace', 'ignore'):
-            raise UnicodeError("Unsupported error handling "+errors)
+            raise UnicodeError(f"Unsupported error handling: {errors}")
         res = punycode_decode(input, errors)
         return res, len(input)
 
@@ -214,7 +230,7 @@ def encode(self, input, final=False):
 class IncrementalDecoder(codecs.IncrementalDecoder):
     def decode(self, input, final=False):
         if self.errors not in ('strict', 'replace', 'ignore'):
-            raise UnicodeError("Unsupported error handling "+self.errors)
+            raise UnicodeError(f"Unsupported error handling: {self.errors}")
         return punycode_decode(input, self.errors)
 
 class StreamWriter(Codec,codecs.StreamWriter):
diff --git a/Lib/encodings/undefined.py b/Lib/encodings/undefined.py
index 4690288355..082771e1c8 100644
--- a/Lib/encodings/undefined.py
+++ b/Lib/encodings/undefined.py
@@ -1,6 +1,6 @@
 """ Python 'undefined' Codec
 
-    This codec will always raise a ValueError exception when being
+    This codec will always raise a UnicodeError exception when being
     used. It is intended for use by the site.py file to switch off
     automatic string to Unicode coercion.
 
diff --git a/Lib/encodings/utf_16.py b/Lib/encodings/utf_16.py
index c61248242b..d3b9980026 100644
--- a/Lib/encodings/utf_16.py
+++ b/Lib/encodings/utf_16.py
@@ -64,7 +64,7 @@ def _buffer_decode(self, input, errors, final):
             elif byteorder == 1:
                 self.decoder = codecs.utf_16_be_decode
             elif consumed >= 2:
-                raise UnicodeError("UTF-16 stream does not start with BOM")
+                raise UnicodeDecodeError("utf-16", input, 0, 2, "Stream does not start with BOM")
             return (output, consumed)
         return self.decoder(input, self.errors, final)
 
@@ -138,7 +138,7 @@ def decode(self, input, errors='strict'):
         elif byteorder == 1:
             self.decode = codecs.utf_16_be_decode
         elif consumed>=2:
-            raise UnicodeError("UTF-16 stream does not start with BOM")
+            raise UnicodeDecodeError("utf-16", input, 0, 2, "Stream does not start with BOM")
         return (object, consumed)
 
 ### encodings module API
diff --git a/Lib/encodings/utf_32.py b/Lib/encodings/utf_32.py
index cdf84d1412..1924bedbb7 100644
--- a/Lib/encodings/utf_32.py
+++ b/Lib/encodings/utf_32.py
@@ -59,7 +59,7 @@ def _buffer_decode(self, input, errors, final):
             elif byteorder == 1:
                 self.decoder = codecs.utf_32_be_decode
             elif consumed >= 4:
-                raise UnicodeError("UTF-32 stream does not start with BOM")
+                raise UnicodeDecodeError("utf-32", input, 0, 4, "Stream does not start with BOM")
             return (output, consumed)
         return self.decoder(input, self.errors, final)
 
@@ -132,8 +132,8 @@ def decode(self, input, errors='strict'):
             self.decode = codecs.utf_32_le_decode
         elif byteorder == 1:
             self.decode = codecs.utf_32_be_decode
-        elif consumed>=4:
-            raise UnicodeError("UTF-32 stream does not start with BOM")
+        elif consumed >= 4:
+            raise UnicodeDecodeError("utf-32", input, 0, 4, "Stream does not start with BOM")
         return (object, consumed)
 
 ### encodings module API
diff --git a/Lib/io.py b/Lib/io.py
index c2812876d3..f0e2fa15d5 100644
--- a/Lib/io.py
+++ b/Lib/io.py
@@ -46,23 +46,17 @@
            "BufferedReader", "BufferedWriter", "BufferedRWPair",
            "BufferedRandom", "TextIOBase", "TextIOWrapper",
            "UnsupportedOperation", "SEEK_SET", "SEEK_CUR", "SEEK_END",
-           "DEFAULT_BUFFER_SIZE", "text_encoding",
-           "IncrementalNewlineDecoder"
-           ]
+           "DEFAULT_BUFFER_SIZE", "text_encoding", "IncrementalNewlineDecoder"]
 
 
 import _io
 import abc
 
 from _io import (DEFAULT_BUFFER_SIZE, BlockingIOError, UnsupportedOperation,
-                 open, open_code, BytesIO, StringIO, BufferedReader,
+                 open, open_code, FileIO, BytesIO, StringIO, BufferedReader,
                  BufferedWriter, BufferedRWPair, BufferedRandom,
                  IncrementalNewlineDecoder, text_encoding, TextIOWrapper)
 
-try:
-    from _io import FileIO
-except ImportError:
-    pass
 
 # Pretend this exception was created here.
 UnsupportedOperation.__module__ = "io"
@@ -87,10 +81,7 @@ class BufferedIOBase(_io._BufferedIOBase, IOBase):
 class TextIOBase(_io._TextIOBase, IOBase):
     __doc__ = _io._TextIOBase.__doc__
 
-try:
-    RawIOBase.register(FileIO)
-except NameError:
-    pass
+RawIOBase.register(FileIO)
 
 for klass in (BytesIO, BufferedReader, BufferedWriter, BufferedRandom,
               BufferedRWPair):
diff --git a/Lib/test/test_codecs.py b/Lib/test/test_codecs.py
index f986d85c6d..0d3d8c9e2d 100644
--- a/Lib/test/test_codecs.py
+++ b/Lib/test/test_codecs.py
@@ -762,7 +762,6 @@ def test_only_one_bom(self):
         f = reader(s)
         self.assertEqual(f.read(), "spamspam")
 
-    @unittest.expectedFailure # TODO: RUSTPYTHON;; UTF-16 stream does not start with BOM
     def test_badbom(self):
         s = io.BytesIO(b"\xff\xff")
         f = codecs.getreader(self.encoding)(s)
@@ -1509,7 +1508,6 @@ def test_decode(self):
             puny = puny.decode("ascii").encode("ascii")
             self.assertEqual(uni, puny.decode("punycode"))
 
-    @unittest.expectedFailure # TODO: RUSTPYTHON; b'Pro\xffprostnemluvesky' != b'Pro\xffprostnemluvesky-uyb24dma41a'
     def test_decode_invalid(self):
         testcases = [
             (b"xn--w&", "strict", UnicodeDecodeError("punycode", b"", 5, 6, "")),
@@ -1694,7 +1692,6 @@ def test_decode_invalid(self):
 
 
 class NameprepTest(unittest.TestCase):
-    @unittest.expectedFailure # TODO: RUSTPYTHON; UnicodeError: Invalid character '\u1680'
     def test_nameprep(self):
         from encodings.idna import nameprep
         for pos, (orig, prepped) in enumerate(nameprep_tests):
@@ -1732,7 +1729,6 @@ class IDNACodecTest(unittest.TestCase):
         ("あさ.\u034f", UnicodeEncodeError("idna", "あさ.\u034f", 3, 4, "")),
     ]
 
-    @unittest.expectedFailure # TODO: RUSTPYTHON; 'XN--pythn-mua.org.' != 'pythön.org.'
     def test_builtin_decode(self):
         self.assertEqual(str(b"python.org", "idna"), "python.org")
         self.assertEqual(str(b"python.org.", "idna"), "python.org.")
@@ -1746,7 +1742,6 @@ def test_builtin_decode(self):
         self.assertEqual(str(b"bugs.XN--pythn-mua.org.", "idna"),
                          "bugs.pyth\xf6n.org.")
 
-    @unittest.expectedFailure # TODO: RUSTPYTHON; 'ascii' != 'idna'
     def test_builtin_decode_invalid(self):
         for case, expected in self.invalid_decode_testcases:
             with self.subTest(case=case, expected=expected):
@@ -1764,7 +1759,6 @@ def test_builtin_encode(self):
         self.assertEqual("pyth\xf6n.org".encode("idna"), b"xn--pythn-mua.org")
         self.assertEqual("pyth\xf6n.org.".encode("idna"), b"xn--pythn-mua.org.")
 
-    @unittest.expectedFailure # TODO: RUSTPYTHON; UnicodeError: label empty or too long
     def test_builtin_encode_invalid(self):
         for case, expected in self.invalid_encode_testcases:
             with self.subTest(case=case, expected=expected):
@@ -1776,7 +1770,6 @@ def test_builtin_encode_invalid(self):
                 self.assertEqual(exc.start, expected.start)
                 self.assertEqual(exc.end, expected.end)
 
-    @unittest.expectedFailure # TODO: RUSTPYTHON; UnicodeError: label empty or too long
     def test_builtin_decode_length_limit(self):
         with self.assertRaisesRegex(UnicodeDecodeError, "way too long"):
             (b"xn--016c"+b"a"*1100).decode("idna")
@@ -1818,7 +1811,6 @@ def test_incremental_decode(self):
         self.assertEqual(decoder.decode(b"rg."), "org.")
         self.assertEqual(decoder.decode(b"", True), "")
 
-    @unittest.expectedFailure # TODO: RUSTPYTHON; 'ascii' != 'idna'
     def test_incremental_decode_invalid(self):
         iterdecode_testcases = [
             (b"\xFFpython.org", UnicodeDecodeError("idna", b"\xFF", 0, 1, "")),
@@ -1880,7 +1872,6 @@ def test_incremental_encode(self):
         self.assertEqual(encoder.encode("ample.org."), b"xn--xample-9ta.org.")
         self.assertEqual(encoder.encode("", True), b"")
 
-    @unittest.expectedFailure # TODO: RUSTPYTHON; UnicodeError: label empty or too long
     def test_incremental_encode_invalid(self):
         iterencode_testcases = [
             (f"foo.{'\xff'*60}", UnicodeEncodeError("idna", f"{'\xff'*60}", 0, 60, "")),
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index e91d454b72..272098782d 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -39,11 +39,9 @@
 from test import support
 from test.support.script_helper import (
     assert_python_ok, assert_python_failure, run_python_until_end)
-from test.support import import_helper
-from test.support import os_helper
-from test.support import threading_helper
-from test.support import warnings_helper
-from test.support import skip_if_sanitizer
+from test.support import (
+    import_helper, is_apple, os_helper, threading_helper, warnings_helper,
+)
 from test.support.os_helper import FakePath
 
 import codecs
@@ -66,10 +64,6 @@ def byteslike(*pos, **kw):
     class EmptyStruct(ctypes.Structure):
         pass
 
-# Does io.IOBase finalizer log the exception if the close() method fails?
-# The exception is ignored silently by default in release build.
-IOBASE_EMITS_UNRAISABLE = (support.Py_DEBUG or sys.flags.dev_mode)
-
 
 def _default_chunk_size():
     """Get the default TextIOWrapper chunk size"""
@@ -631,10 +625,10 @@ def test_raw_bytes_io(self):
         self.read_ops(f, True)
 
     def test_large_file_ops(self):
-        # On Windows and Mac OSX this test consumes large resources; It takes
-        # a long time to build the >2 GiB file and takes >2 GiB of disk space
-        # therefore the resource must be enabled to run this test.
-        if sys.platform[:3] == 'win' or sys.platform == 'darwin':
+        # On Windows and Apple platforms this test consumes large resources; It
+        # takes a long time to build the >2 GiB file and takes >2 GiB of disk
+        # space therefore the resource must be enabled to run this test.
+        if sys.platform[:3] == 'win' or is_apple:
             support.requires(
                 'largefile',
                 'test requires %s bytes and a long time to run' % self.LARGE)
@@ -645,11 +639,9 @@ def test_large_file_ops(self):
 
     def test_with_open(self):
         for bufsize in (0, 100):
-            f = None
             with self.open(os_helper.TESTFN, "wb", bufsize) as f:
                 f.write(b"xxx")
             self.assertEqual(f.closed, True)
-            f = None
             try:
                 with self.open(os_helper.TESTFN, "wb", bufsize) as f:
                     1/0
@@ -788,8 +780,7 @@ def test_closefd_attr(self):
             file = self.open(f.fileno(), "r", encoding="utf-8", closefd=False)
             self.assertEqual(file.buffer.raw.closefd, False)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_garbage_collection(self):
         # FileIO objects are collected, and collecting them flushes
         # all data to disk.
@@ -904,7 +895,7 @@ def test_bad_opener_negative_1(self):
         def badopener(fname, flags):
             return -1
         with self.assertRaises(ValueError) as cm:
-            open('non-existent', 'r', opener=badopener)
+            self.open('non-existent', 'r', opener=badopener)
         self.assertEqual(str(cm.exception), 'opener returned -1')
 
     def test_bad_opener_other_negative(self):
@@ -912,7 +903,7 @@ def test_bad_opener_other_negative(self):
         def badopener(fname, flags):
             return -2
         with self.assertRaises(ValueError) as cm:
-            open('non-existent', 'r', opener=badopener)
+            self.open('non-existent', 'r', opener=badopener)
         self.assertEqual(str(cm.exception), 'opener returned -2')
 
     def test_opener_invalid_fd(self):
@@ -1048,11 +1039,41 @@ def flush(self):
         # Silence destructor error
         R.flush = lambda self: None
 
+    @threading_helper.requires_working_threading()
+    def test_write_readline_races(self):
+        # gh-134908: Concurrent iteration over a file caused races
+        thread_count = 2
+        write_count = 100
+        read_count = 100
+
+        def writer(file, barrier):
+            barrier.wait()
+            for _ in range(write_count):
+                file.write("x")
+
+        def reader(file, barrier):
+            barrier.wait()
+            for _ in range(read_count):
+                for line in file:
+                    self.assertEqual(line, "")
+
+        with self.open(os_helper.TESTFN, "w+") as f:
+            barrier = threading.Barrier(thread_count + 1)
+            reader = threading.Thread(target=reader, args=(f, barrier))
+            writers = [threading.Thread(target=writer, args=(f, barrier))
+                       for _ in range(thread_count)]
+            with threading_helper.catch_threading_exception() as cm:
+                with threading_helper.start_threads(writers + [reader]):
+                    pass
+                self.assertIsNone(cm.exc_type)
+
+        self.assertEqual(os.stat(os_helper.TESTFN).st_size,
+                         write_count * thread_count)
+
 
 class CIOTest(IOTest):
 
-    # TODO: RUSTPYTHON, cyclic gc
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON; cyclic gc
     def test_IOBase_finalize(self):
         # Issue #12149: segmentation fault on _PyIOBase_finalize when both a
         # class which inherits IOBase and an object of this class are caught
@@ -1071,10 +1092,9 @@ def close(self):
         support.gc_collect()
         self.assertIsNone(wr(), wr)
 
-    # TODO: RUSTPYTHON, AssertionError: filter ('', ResourceWarning) did not catch any warning
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON; AssertionError: filter ('', ResourceWarning) did not catch any warning
     def test_destructor(self):
-        super().test_destructor(self)
+        return super().test_destructor()
 
 @support.cpython_only
 class TestIOCTypes(unittest.TestCase):
@@ -1165,9 +1185,32 @@ def test_disallow_instantiation(self):
         _io = self._io
         support.check_disallow_instantiation(self, _io._BytesIOBuffer)
 
+    def test_stringio_setstate(self):
+        # gh-127182: Calling __setstate__() with invalid arguments must not crash
+        obj = self._io.StringIO()
+        with self.assertRaisesRegex(
+            TypeError,
+            'initial_value must be str or None, not int',
+        ):
+            obj.__setstate__((1, '', 0, {}))
+
+        obj.__setstate__((None, '', 0, {}))  # should not crash
+        self.assertEqual(obj.getvalue(), '')
+
+        obj.__setstate__(('', '', 0, {}))
+        self.assertEqual(obj.getvalue(), '')
+
 class PyIOTest(IOTest):
     pass
 
+    @unittest.expectedFailure # TODO: RUSTPYTHON; OSError: Negative file descriptor
+    def test_bad_opener_negative_1():
+        return super().test_bad_opener_negative_1()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON; OSError: Negative file descriptor
+    def test_bad_opener_other_negative():
+        return super().test_bad_opener_other_negative()
+
 
 @support.cpython_only
 class APIMismatchTest(unittest.TestCase):
@@ -1175,7 +1218,7 @@ class APIMismatchTest(unittest.TestCase):
     def test_RawIOBase_io_in_pyio_match(self):
         """Test that pyio RawIOBase class has all c RawIOBase methods"""
         mismatch = support.detect_api_mismatch(pyio.RawIOBase, io.RawIOBase,
-                                               ignore=('__weakref__',))
+                                               ignore=('__weakref__', '__static_attributes__'))
         self.assertEqual(mismatch, set(), msg='Python RawIOBase does not have all C RawIOBase methods')
 
     def test_RawIOBase_pyio_in_io_match(self):
@@ -1244,6 +1287,7 @@ def _with():
         # a ValueError.
         self.assertRaises(ValueError, _with)
 
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_error_through_destructor(self):
         # Test that the exception state is not modified by a destructor,
         # even if close() fails.
@@ -1252,10 +1296,7 @@ def test_error_through_destructor(self):
             with self.assertRaises(AttributeError):
                 self.tp(rawio).xyzzy
 
-            if not IOBASE_EMITS_UNRAISABLE:
-                self.assertIsNone(cm.unraisable)
-            elif cm.unraisable is not None:
-                self.assertEqual(cm.unraisable.exc_type, OSError)
+            self.assertEqual(cm.unraisable.exc_type, OSError)
 
     def test_repr(self):
         raw = self.MockRawIO()
@@ -1271,11 +1312,9 @@ def test_recursive_repr(self):
         # Issue #25455
         raw = self.MockRawIO()
         b = self.tp(raw)
-        with support.swap_attr(raw, 'name', b):
-            try:
+        with support.swap_attr(raw, 'name', b), support.infinite_recursion(25):
+            with self.assertRaises(RuntimeError):
                 repr(b)  # Should not crash
-            except RuntimeError:
-                pass
 
     def test_flush_error_on_close(self):
         # Test that buffered file is closed despite failed flush
@@ -1356,6 +1395,28 @@ def test_readonly_attributes(self):
         with self.assertRaises(AttributeError):
             buf.raw = x
 
+    def test_pickling_subclass(self):
+        global MyBufferedIO
+        class MyBufferedIO(self.tp):
+            def __init__(self, raw, tag):
+                super().__init__(raw)
+                self.tag = tag
+            def __getstate__(self):
+                return self.tag, self.raw.getvalue()
+            def __setstate__(slf, state):
+                tag, value = state
+                slf.__init__(self.BytesIO(value), tag)
+
+        raw = self.BytesIO(b'data')
+        buf = MyBufferedIO(raw, tag='ham')
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.subTest(protocol=proto):
+                pickled = pickle.dumps(buf, proto)
+                newbuf = pickle.loads(pickled)
+                self.assertEqual(newbuf.raw.getvalue(), b'data')
+                self.assertEqual(newbuf.tag, 'ham')
+        del MyBufferedIO
+
 
 class SizeofTest:
 
@@ -1717,20 +1778,6 @@ def test_seek_character_device_file(self):
 class CBufferedReaderTest(BufferedReaderTest, SizeofTest):
     tp = io.BufferedReader
 
-    @unittest.skip("TODO: RUSTPYTHON, fallible allocation")
-    @skip_if_sanitizer(memory=True, address=True, thread=True,
-                       reason="sanitizer defaults to crashing "
-                       "instead of returning NULL for malloc failure.")
-    def test_constructor(self):
-        BufferedReaderTest.test_constructor(self)
-        # The allocation can succeed on 32-bit builds, e.g. with more
-        # than 2 GiB RAM and a 64-bit kernel.
-        if sys.maxsize > 0x7FFFFFFF:
-            rawio = self.MockRawIO()
-            bufio = self.tp(rawio)
-            self.assertRaises((OverflowError, MemoryError, ValueError),
-                bufio.__init__, rawio, sys.maxsize)
-
     def test_initialization(self):
         rawio = self.MockRawIO([b"abc"])
         bufio = self.tp(rawio)
@@ -1748,8 +1795,7 @@ def test_misbehaved_io_read(self):
         # checking this is not so easy.
         self.assertRaises(OSError, bufio.read, 10)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_garbage_collection(self):
         # C BufferedReader objects are collected.
         # The Python version has __del__, so it ends into gc.garbage instead
@@ -1766,40 +1812,44 @@ def test_garbage_collection(self):
     def test_args_error(self):
         # Issue #17275
         with self.assertRaisesRegex(TypeError, "BufferedReader"):
-            self.tp(io.BytesIO(), 1024, 1024, 1024)
+            self.tp(self.BytesIO(), 1024, 1024, 1024)
 
     def test_bad_readinto_value(self):
-        rawio = io.BufferedReader(io.BytesIO(b"12"))
+        rawio = self.tp(self.BytesIO(b"12"))
         rawio.readinto = lambda buf: -1
         bufio = self.tp(rawio)
         with self.assertRaises(OSError) as cm:
             bufio.readline()
         self.assertIsNone(cm.exception.__cause__)
 
-    # TODO: RUSTPYTHON, TypeError: 'bytes' object cannot be interpreted as an integer")
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON; TypeError: 'bytes' object cannot be interpreted as an integer")
     def test_bad_readinto_type(self):
-        rawio = io.BufferedReader(io.BytesIO(b"12"))
+        rawio = self.tp(self.BytesIO(b"12"))
         rawio.readinto = lambda buf: b''
         bufio = self.tp(rawio)
         with self.assertRaises(OSError) as cm:
             bufio.readline()
         self.assertIsInstance(cm.exception.__cause__, TypeError)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_flush_error_on_close(self):
-        super().test_flush_error_on_close()
-
-    # TODO: RUSTPYTHON, AssertionError: UnsupportedOperation not raised by truncate
-    @unittest.expectedFailure
-    def test_truncate_on_read_only(self): # TODO: RUSTPYTHON, remove when this passes
-        super().test_truncate_on_read_only() # TODO: RUSTPYTHON, remove when this passes
+        return super().test_flush_error_on_close()
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_seek_character_device_file(self):
-        super().test_seek_character_device_file()
+        return super().test_seek_character_device_file()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON; AssertionError: UnsupportedOperation not raised by truncate
+    def test_truncate_on_read_only(self):
+        return super().test_truncate_on_read_only()
+
+    @unittest.skip('TODO: RUSTPYTHON; fallible allocation')
+    def test_constructor(self):
+        return super().test_constructor()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_pickling_subclass(self):
+        return super().test_pickling_subclass()
 
 
 class PyBufferedReaderTest(BufferedReaderTest):
@@ -1909,8 +1959,7 @@ def _seekrel(bufio):
     def test_writes_and_truncates(self):
         self.check_writes(lambda bufio: bufio.truncate(bufio.tell()))
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_write_non_blocking(self):
         raw = self.MockNonBlockWriterIO()
         bufio = self.tp(raw, 8)
@@ -2107,20 +2156,6 @@ def test_slow_close_from_thread(self):
 class CBufferedWriterTest(BufferedWriterTest, SizeofTest):
     tp = io.BufferedWriter
 
-    @unittest.skip("TODO: RUSTPYTHON, fallible allocation")
-    @skip_if_sanitizer(memory=True, address=True, thread=True,
-                       reason="sanitizer defaults to crashing "
-                       "instead of returning NULL for malloc failure.")
-    def test_constructor(self):
-        BufferedWriterTest.test_constructor(self)
-        # The allocation can succeed on 32-bit builds, e.g. with more
-        # than 2 GiB RAM and a 64-bit kernel.
-        if sys.maxsize > 0x7FFFFFFF:
-            rawio = self.MockRawIO()
-            bufio = self.tp(rawio)
-            self.assertRaises((OverflowError, MemoryError, ValueError),
-                bufio.__init__, rawio, sys.maxsize)
-
     def test_initialization(self):
         rawio = self.MockRawIO()
         bufio = self.tp(rawio)
@@ -2131,8 +2166,7 @@ def test_initialization(self):
         self.assertRaises(ValueError, bufio.__init__, rawio, buffer_size=-1)
         self.assertRaises(ValueError, bufio.write, b"def")
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_garbage_collection(self):
         # C BufferedWriter objects are collected, and collecting them flushes
         # all data to disk.
@@ -2155,11 +2189,17 @@ def test_args_error(self):
         with self.assertRaisesRegex(TypeError, "BufferedWriter"):
             self.tp(self.BytesIO(), 1024, 1024, 1024)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_flush_error_on_close(self):
-        super().test_flush_error_on_close()
+        return super().test_flush_error_on_close()
+
+    @unittest.skip('TODO: RUSTPYTHON; fallible allocation')
+    def test_constructor(self):
+        return super().test_constructor()
 
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_pickling_subclass(self):
+        return super().test_pickling_subclass()
 
 class PyBufferedWriterTest(BufferedWriterTest):
     tp = pyio.BufferedWriter
@@ -2637,22 +2677,7 @@ def test_interleaved_readline_write(self):
 class CBufferedRandomTest(BufferedRandomTest, SizeofTest):
     tp = io.BufferedRandom
 
-    @unittest.skip("TODO: RUSTPYTHON, fallible allocation")
-    @skip_if_sanitizer(memory=True, address=True, thread=True,
-                       reason="sanitizer defaults to crashing "
-                       "instead of returning NULL for malloc failure.")
-    def test_constructor(self):
-        BufferedRandomTest.test_constructor(self)
-        # The allocation can succeed on 32-bit builds, e.g. with more
-        # than 2 GiB RAM and a 64-bit kernel.
-        if sys.maxsize > 0x7FFFFFFF:
-            rawio = self.MockRawIO()
-            bufio = self.tp(rawio)
-            self.assertRaises((OverflowError, MemoryError, ValueError),
-                bufio.__init__, rawio, sys.maxsize)
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_garbage_collection(self):
         CBufferedReaderTest.test_garbage_collection(self)
         CBufferedWriterTest.test_garbage_collection(self)
@@ -2662,20 +2687,25 @@ def test_args_error(self):
         with self.assertRaisesRegex(TypeError, "BufferedRandom"):
             self.tp(self.BytesIO(), 1024, 1024, 1024)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_flush_error_on_close(self):
-        super().test_flush_error_on_close()
+        return super().test_flush_error_on_close()
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_seek_character_device_file(self):
-        super().test_seek_character_device_file()
+        return super().test_seek_character_device_file()
 
-    # TODO: RUSTPYTHON; f.read1(1) returns b'a'
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON; f.read1(1) returns b'a'
     def test_read1_after_write(self):
-        super().test_read1_after_write()
+        return super().test_read1_after_write()
+
+    @unittest.skip('TODO: RUSTPYTHON; fallible allocation')
+    def test_constructor(self):
+        return super().test_constructor()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_pickling_subclass(self):
+        return super().test_pickling_subclass()
 
 
 class PyBufferedRandomTest(BufferedRandomTest):
@@ -2935,11 +2965,16 @@ def test_recursive_repr(self):
         # Issue #25455
         raw = self.BytesIO()
         t = self.TextIOWrapper(raw, encoding="utf-8")
-        with support.swap_attr(raw, 'name', t):
-            try:
+        with support.swap_attr(raw, 'name', t), support.infinite_recursion(25):
+            with self.assertRaises(RuntimeError):
                 repr(t)  # Should not crash
-            except RuntimeError:
-                pass
+
+    def test_subclass_repr(self):
+        class TestSubclass(self.TextIOWrapper):
+            pass
+
+        f = TestSubclass(self.StringIO())
+        self.assertIn(TestSubclass.__name__, repr(f))
 
     def test_line_buffering(self):
         r = self.BytesIO()
@@ -3166,6 +3201,7 @@ def flush(self):
         support.gc_collect()
         self.assertEqual(record, [1, 2, 3])
 
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_error_through_destructor(self):
         # Test that the exception state is not modified by a destructor,
         # even if close() fails.
@@ -3174,10 +3210,7 @@ def test_error_through_destructor(self):
             with self.assertRaises(AttributeError):
                 self.TextIOWrapper(rawio, encoding="utf-8").xyzzy
 
-            if not IOBASE_EMITS_UNRAISABLE:
-                self.assertIsNone(cm.unraisable)
-            elif cm.unraisable is not None:
-                self.assertEqual(cm.unraisable.exc_type, OSError)
+            self.assertEqual(cm.unraisable.exc_type, OSError)
 
     # Systematic tests of the text I/O API
 
@@ -3327,8 +3360,7 @@ def test_seek_and_tell_with_data(data, min_pos=0):
         finally:
             StatefulIncrementalDecoder.codecEnabled = 0
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_multibyte_seek_and_tell(self):
         f = self.open(os_helper.TESTFN, "w", encoding="euc_jp")
         f.write("AB\n\u3046\u3048\n")
@@ -3344,8 +3376,7 @@ def test_multibyte_seek_and_tell(self):
         self.assertEqual(f.tell(), p1)
         f.close()
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_seek_with_encoder_state(self):
         f = self.open(os_helper.TESTFN, "w", encoding="euc_jis_2004")
         f.write("\u00e6\u0300")
@@ -3359,8 +3390,7 @@ def test_seek_with_encoder_state(self):
         self.assertEqual(f.readline(), "\u00e6\u0300\u0300")
         f.close()
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_encoded_writes(self):
         data = "1234567890"
         tests = ("utf-16",
@@ -3499,8 +3529,7 @@ def test_issue2282(self):
 
         self.assertEqual(buffer.seekable(), txt.seekable())
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_append_bom(self):
         # The BOM is not written again when appending to a non-empty file
         filename = os_helper.TESTFN
@@ -3516,8 +3545,7 @@ def test_append_bom(self):
             with self.open(filename, 'rb') as f:
                 self.assertEqual(f.read(), 'aaaxxx'.encode(charset))
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_seek_bom(self):
         # Same test, but when seeking manually
         filename = os_helper.TESTFN
@@ -3533,8 +3561,7 @@ def test_seek_bom(self):
             with self.open(filename, 'rb') as f:
                 self.assertEqual(f.read(), 'bbbzzz'.encode(charset))
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_seek_append_bom(self):
         # Same test, but first seek to the start and then to the end
         filename = os_helper.TESTFN
@@ -3795,17 +3822,14 @@ def _check_create_at_shutdown(self, **kwargs):
             codecs.lookup('utf-8')
 
             class C:
-                def __init__(self):
-                    self.buf = io.BytesIO()
                 def __del__(self):
-                    io.TextIOWrapper(self.buf, **{kwargs})
+                    io.TextIOWrapper(io.BytesIO(), **{kwargs})
                     print("ok")
             c = C()
             """.format(iomod=iomod, kwargs=kwargs)
         return assert_python_ok("-c", code)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_create_at_shutdown_without_encoding(self):
         rc, out, err = self._check_create_at_shutdown()
         if err:
@@ -3815,8 +3839,7 @@ def test_create_at_shutdown_without_encoding(self):
         else:
             self.assertEqual("ok", out.decode().strip())
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_create_at_shutdown_with_encoding(self):
         rc, out, err = self._check_create_at_shutdown(encoding='utf-8',
                                                       errors='strict')
@@ -4042,6 +4065,28 @@ def test_issue35928(self):
         f.write(res)
         self.assertEqual(res + f.readline(), 'foo\nbar\n')
 
+    def test_pickling_subclass(self):
+        global MyTextIO
+        class MyTextIO(self.TextIOWrapper):
+            def __init__(self, raw, tag):
+                super().__init__(raw)
+                self.tag = tag
+            def __getstate__(self):
+                return self.tag, self.buffer.getvalue()
+            def __setstate__(slf, state):
+                tag, value = state
+                slf.__init__(self.BytesIO(value), tag)
+
+        raw = self.BytesIO(b'data')
+        txt = MyTextIO(raw, 'ham')
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.subTest(protocol=proto):
+                pickled = pickle.dumps(txt, proto)
+                newtxt = pickle.loads(pickled)
+                self.assertEqual(newtxt.buffer.getvalue(), b'data')
+                self.assertEqual(newtxt.tag, 'ham')
+        del MyTextIO
+
 
 class MemviewBytesIO(io.BytesIO):
     '''A BytesIO object whose read method returns memoryviews
@@ -4066,98 +4111,7 @@ class CTextIOWrapperTest(TextIOWrapperTest):
     io = io
     shutdown_error = "LookupError: unknown encoding: ascii"
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_constructor(self):
-        super().test_constructor()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_detach(self):
-        super().test_detach()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_reconfigure_encoding_read(self):
-        super().test_reconfigure_encoding_read()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_reconfigure_line_buffering(self):
-        super().test_reconfigure_line_buffering()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_basic_io(self):
-        super().test_basic_io()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_telling(self):
-        super().test_telling()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_uninitialized(self):
-        super().test_uninitialized()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_non_text_encoding_codecs_are_rejected(self):
-        super().test_non_text_encoding_codecs_are_rejected()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_repr(self):
-        super().test_repr()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_newlines(self):
-        super().test_newlines()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_newlines_input(self):
-        super().test_newlines_input()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_reconfigure_write_through(self):
-        super().test_reconfigure_write_through()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_reconfigure_write_fromascii(self):
-        super().test_reconfigure_write_fromascii()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_reconfigure_write(self):
-        super().test_reconfigure_write()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_reconfigure_defaults(self):
-        super().test_reconfigure_defaults()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_reconfigure_newline(self):
-        super().test_reconfigure_newline()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_reconfigure_errors(self):
-        super().test_reconfigure_errors()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_reconfigure_locale(self):
-        super().test_reconfigure_locale()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_initialization(self):
         r = self.BytesIO(b"\xc3\xa9\n\n")
         b = self.BufferedReader(r, 1000)
@@ -4168,8 +4122,7 @@ def test_initialization(self):
         t = self.TextIOWrapper.__new__(self.TextIOWrapper)
         self.assertRaises(Exception, repr, t)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_garbage_collection(self):
         # C TextIOWrapper objects are collected, and collecting them flushes
         # all data to disk.
@@ -4233,20 +4186,121 @@ def write(self, data):
         t.write("x"*chunk_size)
         self.assertEqual([b"abcdef", b"ghi", b"x"*chunk_size], buf._write_stack)
 
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_issue119506(self):
+        chunk_size = 8192
+
+        class MockIO(self.MockRawIO):
+            written = False
+            def write(self, data):
+                if not self.written:
+                    self.written = True
+                    t.write("middle")
+                return super().write(data)
+
+        buf = MockIO()
+        t = self.TextIOWrapper(buf)
+        t.write("abc")
+        t.write("def")
+        # writing data which size >= chunk_size cause flushing buffer before write.
+        t.write("g" * chunk_size)
+        t.flush()
+
+        self.assertEqual([b"abcdef", b"middle", b"g"*chunk_size],
+                         buf._write_stack)
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_basic_io(self):
+        return super().test_basic_io()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_constructor(self):
+        return super().test_constructor()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_detach(self):
+        return super().test_detach()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_newlines(self):
+        return super().test_newlines()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_newlines_input(self):
+        return super().test_newlines_input()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_non_text_encoding_codecs_are_rejected(self):
+        return super().test_non_text_encoding_codecs_are_rejected()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_reconfigure_defaults(self):
+        return super().test_reconfigure_defaults()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_reconfigure_encoding_read(self):
+        return super().test_reconfigure_encoding_read()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_reconfigure_errors(self):
+        return super().test_reconfigure_errors()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_reconfigure_line_buffering(self):
+        return super().test_reconfigure_line_buffering()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_reconfigure_locale(self):
+        return super().test_reconfigure_locale()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_reconfigure_newline(self):
+        return super().test_reconfigure_newline()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_reconfigure_write(self):
+        return super().test_reconfigure_write()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_reconfigure_write_fromascii(self):
+        return super().test_reconfigure_write_fromascii()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_reconfigure_write_through(self):
+        return super().test_reconfigure_write_through()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_repr(self):
+        return super().test_repr()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_telling(self):
+        return super().test_telling()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_uninitialized(self):
+        return super().test_uninitialized()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_recursive_repr(self):
+        return super().test_recursive_repr()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_pickling_subclass(self):
+        return super().test_pickling_subclass()
+
 
 class PyTextIOWrapperTest(TextIOWrapperTest):
     io = pyio
     shutdown_error = "LookupError: unknown encoding: ascii"
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON; AssertionError: ValueError not raised
     def test_constructor(self):
-        super().test_constructor()
+        return super().test_constructor()
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_newlines(self):
-        super().test_newlines()
+        return super().test_newlines()
 
 
 class IncrementalNewlineDecoderTest(unittest.TestCase):
@@ -4326,8 +4380,7 @@ def _decode_bytewise(s):
         self.assertEqual(decoder.decode(input), "abc")
         self.assertEqual(decoder.newlines, None)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_newline_decoder(self):
         encodings = (
             # None meaning the IncrementalNewlineDecoder takes unicode input
@@ -4489,8 +4542,7 @@ def test_io_after_close(self):
             self.assertRaises(ValueError, f.writelines, [])
             self.assertRaises(ValueError, next, f)
 
-    # TODO: RUSTPYTHON, cyclic gc
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON; cyclic gc
     def test_blockingioerror(self):
         # Various BlockingIOError issues
         class C(str):
@@ -4538,15 +4590,14 @@ def test_abc_inheritance_official(self):
         self._check_abc_inheritance(io)
 
     def _check_warn_on_dealloc(self, *args, **kwargs):
-        f = open(*args, **kwargs)
+        f = self.open(*args, **kwargs)
         r = repr(f)
         with self.assertWarns(ResourceWarning) as cm:
             f = None
             support.gc_collect()
         self.assertIn(r, str(cm.warning.args[0]))
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_warn_on_dealloc(self):
         self._check_warn_on_dealloc(os_helper.TESTFN, "wb", buffering=0)
         self._check_warn_on_dealloc(os_helper.TESTFN, "wb")
@@ -4569,10 +4620,9 @@ def cleanup_fds():
         r, w = os.pipe()
         fds += r, w
         with warnings_helper.check_no_resource_warning(self):
-            open(r, *args, closefd=False, **kwargs)
+            self.open(r, *args, closefd=False, **kwargs)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     @unittest.skipUnless(hasattr(os, "pipe"), "requires os.pipe()")
     def test_warn_on_dealloc_fd(self):
         self._check_warn_on_dealloc_fd("rb", buffering=0)
@@ -4602,16 +4652,14 @@ def test_pickling(self):
                         with self.assertRaisesRegex(TypeError, msg):
                             pickle.dumps(f, protocol)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     @unittest.skipIf(
         support.is_emscripten, "fstat() of a pipe fd is not supported"
     )
     def test_nonblock_pipe_write_bigbuf(self):
         self._test_nonblock_pipe_write(16*1024)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     @unittest.skipIf(
         support.is_emscripten, "fstat() of a pipe fd is not supported"
     )
@@ -4733,8 +4781,7 @@ def test_check_encoding_errors(self):
         proc = assert_python_failure('-X', 'dev', '-c', code)
         self.assertEqual(proc.rc, 10, proc)
 
-    # TODO: RUSTPYTHON, AssertionError: 0 != 2
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON; AssertionError: 0 != 2
     def test_check_encoding_warning(self):
         # PEP 597: Raise warning when encoding is not specified
         # and sys.flags.warn_default_encoding is set.
@@ -4758,8 +4805,7 @@ def test_check_encoding_warning(self):
         self.assertTrue(
             warnings[1].startswith(b"<string>:8: EncodingWarning: "))
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_text_encoding(self):
         # PEP 597, bpo-47000. io.text_encoding() returns "locale" or "utf-8"
         # based on sys.flags.utf8_mode
@@ -4837,10 +4883,9 @@ def test_daemon_threads_shutdown_stdout_deadlock(self):
     def test_daemon_threads_shutdown_stderr_deadlock(self):
         self.check_daemon_threads_shutdown_deadlock('stderr')
 
-    # TODO: RUSTPYTHON, AssertionError: 22 != 10 : _PythonRunResult(rc=22, out=b'', err=b'')
-    @unittest.expectedFailure
-    def test_check_encoding_errors(self): # TODO: RUSTPYTHON, remove when this passes
-        super().test_check_encoding_errors() # TODO: RUSTPYTHON, remove when this passes
+    @unittest.expectedFailure # TODO: RUSTPYTHON; AssertionError: 22 != 10 : _PythonRunResult(rc=22, out=b'', err=b'')
+    def test_check_encoding_errors(self):
+        return super().test_check_encoding_errors()
 
 
 class PyMiscIOTest(MiscIOTest):
@@ -5014,16 +5059,14 @@ def alarm_handler(sig, frame):
             os.close(w)
             os.close(r)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     @requires_alarm
     @support.requires_resource('walltime')
     def test_interrupted_read_retry_buffered(self):
         self.check_interrupted_read_retry(lambda x: x.decode('latin1'),
                                           mode="rb")
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     @requires_alarm
     @support.requires_resource('walltime')
     def test_interrupted_read_retry_text(self):
@@ -5098,15 +5141,13 @@ def alarm2(sig, frame):
                 if e.errno != errno.EBADF:
                     raise
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     @requires_alarm
     @support.requires_resource('walltime')
     def test_interrupted_write_retry_buffered(self):
         self.check_interrupted_write_retry(b"x", mode="wb")
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     @requires_alarm
     @support.requires_resource('walltime')
     def test_interrupted_write_retry_text(self):