diff --git a/Lib/test/string_tests.py b/Lib/test/string_tests.py
index d505c6000..4a41e5810 100644
--- a/Lib/test/string_tests.py
+++ b/Lib/test/string_tests.py
@@ -92,6 +92,7 @@ class BaseTest:
         args = self.fixtype(args)
         getattr(obj, methodname)(*args)
 
+    @unittest.skip("TODO: RUSTPYTHON test_bytes")
     def test_count(self):
         self.checkequal(3, 'aaa', 'count', 'a')
         self.checkequal(0, 'aaa', 'count', 'b')
@@ -156,6 +157,7 @@ class BaseTest:
                     self.assertEqual(rem, 0, '%s != 0 for %s' % (rem, i))
                     self.assertEqual(r1, r2, '%s != %s for %s' % (r1, r2, i))
 
+    @unittest.skip("TODO: RUSTPYTHON test_bytes")
     def test_find(self):
         self.checkequal(0, 'abcdefghiabc', 'find', 'abc')
         self.checkequal(9, 'abcdefghiabc', 'find', 'abc', 1)
@@ -213,6 +215,7 @@ class BaseTest:
                 if loc != -1:
                     self.assertEqual(i[loc:loc+len(j)], j)
 
+    @unittest.skip("TODO: RUSTPYTHON test_bytes")
     def test_rfind(self):
         self.checkequal(9,  'abcdefghiabc', 'rfind', 'abc')
         self.checkequal(12, 'abcdefghiabc', 'rfind', '')
@@ -291,6 +294,7 @@ class BaseTest:
         else:
             self.checkraises(TypeError, 'hello', 'index', 42)
 
+    @unittest.skip("TODO: RUSTPYTHON test_bytes")
     def test_rindex(self):
         self.checkequal(12, 'abcdefghiabc', 'rindex', '')
         self.checkequal(3,  'abcdefghiabc', 'rindex', 'def')
@@ -356,6 +360,7 @@ class BaseTest:
             self.checkraises(OverflowError,
                              '\ta\n\tb', 'expandtabs', sys.maxsize)
 
+    @unittest.skip("TODO: RUSTPYTHON test_bytes")
     def test_split(self):
         # by a char
         self.checkequal(['a', 'b', 'c', 'd'], 'a|b|c|d', 'split', '|')
@@ -426,6 +431,7 @@ class BaseTest:
         self.checkraises(ValueError, 'hello', 'split', '')
         self.checkraises(ValueError, 'hello', 'split', '', 0)
 
+    @unittest.skip("TODO: RUSTPYTHON test_bytes")
     def test_rsplit(self):
         # by a char
         self.checkequal(['a', 'b', 'c', 'd'], 'a|b|c|d', 'rsplit', '|')
@@ -496,6 +502,7 @@ class BaseTest:
         self.checkraises(ValueError, 'hello', 'rsplit', '')
         self.checkraises(ValueError, 'hello', 'rsplit', '', 0)
 
+    @unittest.skip("TODO: RUSTPYTHON test_bytes")
     def test_replace(self):
         EQ = self.checkequal
 
@@ -770,6 +777,7 @@ class BaseTest:
             self.checkequal(['arf', 'barf'], b, 'rsplit', None)
             self.checkequal(['arf', 'barf'], b, 'rsplit', None, 2)
 
+    @unittest.skip("TODO: RUSTPYTHON test_bytes")
     def test_strip_whitespace(self):
         self.checkequal('hello', '   hello   ', 'strip')
         self.checkequal('hello   ', '   hello   ', 'lstrip')
@@ -787,6 +795,7 @@ class BaseTest:
         self.checkequal('   hello', '   hello   ', 'rstrip', None)
         self.checkequal('hello', 'hello', 'strip', None)
 
+    @unittest.skip("TODO: RUSTPYTHON test_bytes")
     def test_strip(self):
         # strip/lstrip/rstrip with str arg
         self.checkequal('hello', 'xyzzyhelloxyzzy', 'strip', 'xyz')
@@ -831,6 +840,7 @@ class BaseTest:
 
         self.checkraises(TypeError, 'hello', 'swapcase', 42)
 
+    @unittest.skip("TODO: RUSTPYTHON test_bytes")
     def test_zfill(self):
         self.checkequal('123', '123', 'zfill', 2)
         self.checkequal('123', '123', 'zfill', 3)
@@ -847,6 +857,7 @@ class BaseTest:
 
         self.checkraises(TypeError, '123', 'zfill')
 
+    @unittest.skip("TODO: RUSTPYTHON test_bytes")
     def test_islower(self):
         self.checkequal(False, '', 'islower')
         self.checkequal(True, 'a', 'islower')
@@ -857,6 +868,7 @@ class BaseTest:
         self.checkequal(True, 'abc\n', 'islower')
         self.checkraises(TypeError, 'abc', 'islower', 42)
 
+    @unittest.skip("TODO: RUSTPYTHON test_bytes")
     def test_isupper(self):
         self.checkequal(False, '', 'isupper')
         self.checkequal(False, 'a', 'isupper')
@@ -913,6 +925,7 @@ class BaseTest:
         self.checkequal(False, 'abc\n', 'isalnum')
         self.checkraises(TypeError, 'abc', 'isalnum', 42)
 
+    @unittest.skip("TODO: RUSTPYTHON test_bytes")
     def test_isascii(self):
         self.checkequal(True, '', 'isascii')
         self.checkequal(True, '\x00', 'isascii')
diff --git a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
new file mode 100644
index 000000000..1783da8c1
--- /dev/null
+++ b/Lib/test/test_bytes.py
@@ -0,0 +1,2025 @@
+"""Unit tests for the bytes and bytearray types.
+
+XXX This is a mess.  Common tests should be unified with string_tests.py (and
+the latter should be modernized).
+"""
+
+import array
+import os
+import re
+import sys
+import copy
+import functools
+import pickle
+import tempfile
+import unittest
+
+import test.support
+import test.string_tests
+import test.list_tests
+from test.support import bigaddrspacetest, MAX_Py_ssize_t
+
+
+if sys.flags.bytes_warning:
+    def check_bytes_warnings(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kw):
+            with test.support.check_warnings(('', BytesWarning)):
+                return func(*args, **kw)
+        return wrapper
+else:
+    # no-op
+    def check_bytes_warnings(func):
+        return func
+
+
+class Indexable:
+    def __init__(self, value=0):
+        self.value = value
+    def __index__(self):
+        return self.value
+
+
+class BaseBytesTest:
+
+    def test_basics(self):
+        b = self.type2test()
+        self.assertEqual(type(b), self.type2test)
+        self.assertEqual(b.__class__, self.type2test)
+
+    def test_copy(self):
+        a = self.type2test(b"abcd")
+        for copy_method in (copy.copy, copy.deepcopy):
+            b = copy_method(a)
+            self.assertEqual(a, b)
+            self.assertEqual(type(a), type(b))
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_empty_sequence(self):
+        b = self.type2test()
+        self.assertEqual(len(b), 0)
+        self.assertRaises(IndexError, lambda: b[0])
+        self.assertRaises(IndexError, lambda: b[1])
+        self.assertRaises(IndexError, lambda: b[sys.maxsize])
+        self.assertRaises(IndexError, lambda: b[sys.maxsize+1])
+        self.assertRaises(IndexError, lambda: b[10**100])
+        self.assertRaises(IndexError, lambda: b[-1])
+        self.assertRaises(IndexError, lambda: b[-2])
+        self.assertRaises(IndexError, lambda: b[-sys.maxsize])
+        self.assertRaises(IndexError, lambda: b[-sys.maxsize-1])
+        self.assertRaises(IndexError, lambda: b[-sys.maxsize-2])
+        self.assertRaises(IndexError, lambda: b[-10**100])
+
+    def test_from_iterable(self):
+        b = self.type2test(range(256))
+        self.assertEqual(len(b), 256)
+        self.assertEqual(list(b), list(range(256)))
+
+        # Non-sequence iterable.
+        b = self.type2test({42})
+        self.assertEqual(b, b"*")
+        b = self.type2test({43, 45})
+        self.assertIn(tuple(b), {(43, 45), (45, 43)})
+
+        # Iterator that has a __length_hint__.
+        b = self.type2test(iter(range(256)))
+        self.assertEqual(len(b), 256)
+        self.assertEqual(list(b), list(range(256)))
+
+        # Iterator that doesn't have a __length_hint__.
+        b = self.type2test(i for i in range(256) if i % 2)
+        self.assertEqual(len(b), 128)
+        self.assertEqual(list(b), list(range(256))[1::2])
+
+        # Sequence without __iter__.
+        class S:
+            def __getitem__(self, i):
+                return (1, 2, 3)[i]
+        b = self.type2test(S())
+        self.assertEqual(b, b"\x01\x02\x03")
+
+    def test_from_tuple(self):
+        # There is a special case for tuples.
+        b = self.type2test(tuple(range(256)))
+        self.assertEqual(len(b), 256)
+        self.assertEqual(list(b), list(range(256)))
+        b = self.type2test((1, 2, 3))
+        self.assertEqual(b, b"\x01\x02\x03")
+
+    def test_from_list(self):
+        # There is a special case for lists.
+        b = self.type2test(list(range(256)))
+        self.assertEqual(len(b), 256)
+        self.assertEqual(list(b), list(range(256)))
+        b = self.type2test([1, 2, 3])
+        self.assertEqual(b, b"\x01\x02\x03")
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_from_mutating_list(self):
+        # Issue #34973: Crash in bytes constructor with mutating list.
+        class X:
+            def __index__(self):
+                a.clear()
+                return 42
+        a = [X(), X()]
+        self.assertEqual(bytes(a), b'*')
+
+        class Y:
+            def __index__(self):
+                if len(a) < 1000:
+                    a.append(self)
+                return 42
+        a = [Y()]
+        self.assertEqual(bytes(a), b'*' * 1000)  # should not crash
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_from_index(self):
+        b = self.type2test([Indexable(), Indexable(1), Indexable(254),
+                            Indexable(255)])
+        self.assertEqual(list(b), [0, 1, 254, 255])
+        self.assertRaises(ValueError, self.type2test, [Indexable(-1)])
+        self.assertRaises(ValueError, self.type2test, [Indexable(256)])
+
+    def test_from_buffer(self):
+        a = self.type2test(array.array('B', [1, 2, 3]))
+        self.assertEqual(a, b"\x01\x02\x03")
+        a = self.type2test(b"\x01\x02\x03")
+        self.assertEqual(a, b"\x01\x02\x03")
+
+        # Issues #29159 and #34974.
+        # Fallback when __index__ raises a TypeError
+        class B(bytes):
+            def __index__(self):
+                raise TypeError
+
+        self.assertEqual(self.type2test(B(b"foobar")), b"foobar")
+
+    @unittest.skip("TODO: RUSTPYTHON")
+    def test_from_ssize(self):
+        self.assertEqual(self.type2test(0), b'')
+        self.assertEqual(self.type2test(1), b'\x00')
+        self.assertEqual(self.type2test(5), b'\x00\x00\x00\x00\x00')
+        self.assertRaises(ValueError, self.type2test, -1)
+
+        self.assertEqual(self.type2test('0', 'ascii'), b'0')
+        self.assertEqual(self.type2test(b'0'), b'0')
+        self.assertRaises(OverflowError, self.type2test, sys.maxsize + 1)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_constructor_type_errors(self):
+        self.assertRaises(TypeError, self.type2test, 0.0)
+        class C:
+            pass
+        self.assertRaises(TypeError, self.type2test, ["0"])
+        self.assertRaises(TypeError, self.type2test, [0.0])
+        self.assertRaises(TypeError, self.type2test, [None])
+        self.assertRaises(TypeError, self.type2test, [C()])
+        self.assertRaises(TypeError, self.type2test, encoding='ascii')
+        self.assertRaises(TypeError, self.type2test, errors='ignore')
+        self.assertRaises(TypeError, self.type2test, 0, 'ascii')
+        self.assertRaises(TypeError, self.type2test, b'', 'ascii')
+        self.assertRaises(TypeError, self.type2test, 0, errors='ignore')
+        self.assertRaises(TypeError, self.type2test, b'', errors='ignore')
+        self.assertRaises(TypeError, self.type2test, '')
+        self.assertRaises(TypeError, self.type2test, '', errors='ignore')
+        self.assertRaises(TypeError, self.type2test, '', b'ascii')
+        self.assertRaises(TypeError, self.type2test, '', 'ascii', b'ignore')
+
+    def test_constructor_value_errors(self):
+        self.assertRaises(ValueError, self.type2test, [-1])
+        self.assertRaises(ValueError, self.type2test, [-sys.maxsize])
+        self.assertRaises(ValueError, self.type2test, [-sys.maxsize-1])
+        self.assertRaises(ValueError, self.type2test, [-sys.maxsize-2])
+        self.assertRaises(ValueError, self.type2test, [-10**100])
+        self.assertRaises(ValueError, self.type2test, [256])
+        self.assertRaises(ValueError, self.type2test, [257])
+        self.assertRaises(ValueError, self.type2test, [sys.maxsize])
+        self.assertRaises(ValueError, self.type2test, [sys.maxsize+1])
+        self.assertRaises(ValueError, self.type2test, [10**100])
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    @bigaddrspacetest
+    def test_constructor_overflow(self):
+        size = MAX_Py_ssize_t
+        self.assertRaises((OverflowError, MemoryError), self.type2test, size)
+        try:
+            # Should either pass or raise an error (e.g. on debug builds with
+            # additional malloc() overhead), but shouldn't crash.
+            bytearray(size - 4)
+        except (OverflowError, MemoryError):
+            pass
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_constructor_exceptions(self):
+        # Issue #34974: bytes and bytearray constructors replace unexpected
+        # exceptions.
+        class BadInt:
+            def __index__(self):
+                1/0
+        self.assertRaises(ZeroDivisionError, self.type2test, BadInt())
+        self.assertRaises(ZeroDivisionError, self.type2test, [BadInt()])
+
+        class BadIterable:
+            def __iter__(self):
+                1/0
+        self.assertRaises(ZeroDivisionError, self.type2test, BadIterable())
+
+    def test_compare(self):
+        b1 = self.type2test([1, 2, 3])
+        b2 = self.type2test([1, 2, 3])
+        b3 = self.type2test([1, 3])
+
+        self.assertEqual(b1, b2)
+        self.assertTrue(b2 != b3)
+        self.assertTrue(b1 <= b2)
+        self.assertTrue(b1 <= b3)
+        self.assertTrue(b1 <  b3)
+        self.assertTrue(b1 >= b2)
+        self.assertTrue(b3 >= b2)
+        self.assertTrue(b3 >  b2)
+
+        self.assertFalse(b1 != b2)
+        self.assertFalse(b2 == b3)
+        self.assertFalse(b1 >  b2)
+        self.assertFalse(b1 >  b3)
+        self.assertFalse(b1 >= b3)
+        self.assertFalse(b1 <  b2)
+        self.assertFalse(b3 <  b2)
+        self.assertFalse(b3 <= b2)
+
+    @check_bytes_warnings
+    def test_compare_to_str(self):
+        # Byte comparisons with unicode should always fail!
+        # Test this for all expected byte orders and Unicode character
+        # sizes.
+        self.assertEqual(self.type2test(b"\0a\0b\0c") == "abc", False)
+        self.assertEqual(self.type2test(b"\0\0\0a\0\0\0b\0\0\0c") == "abc",
+                            False)
+        self.assertEqual(self.type2test(b"a\0b\0c\0") == "abc", False)
+        self.assertEqual(self.type2test(b"a\0\0\0b\0\0\0c\0\0\0") == "abc",
+                            False)
+        self.assertEqual(self.type2test() == str(), False)
+        self.assertEqual(self.type2test() != str(), True)
+
+    def test_reversed(self):
+        input = list(map(ord, "Hello"))
+        b = self.type2test(input)
+        output = list(reversed(b))
+        input.reverse()
+        self.assertEqual(output, input)
+
+    def test_getslice(self):
+        def by(s):
+            return self.type2test(map(ord, s))
+        b = by("Hello, world")
+
+        self.assertEqual(b[:5], by("Hello"))
+        self.assertEqual(b[1:5], by("ello"))
+        self.assertEqual(b[5:7], by(", "))
+        self.assertEqual(b[7:], by("world"))
+        self.assertEqual(b[7:12], by("world"))
+        self.assertEqual(b[7:100], by("world"))
+
+        self.assertEqual(b[:-7], by("Hello"))
+        self.assertEqual(b[-11:-7], by("ello"))
+        self.assertEqual(b[-7:-5], by(", "))
+        self.assertEqual(b[-5:], by("world"))
+        self.assertEqual(b[-5:12], by("world"))
+        self.assertEqual(b[-5:100], by("world"))
+        self.assertEqual(b[-100:5], by("Hello"))
+
+    def test_extended_getslice(self):
+        # Test extended slicing by comparing with list slicing.
+        L = list(range(255))
+        b = self.type2test(L)
+        indices = (0, None, 1, 3, 19, 100, sys.maxsize, -1, -2, -31, -100)
+        for start in indices:
+            for stop in indices:
+                # Skip step 0 (invalid)
+                for step in indices[1:]:
+                    self.assertEqual(b[start:stop:step], self.type2test(L[start:stop:step]))
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_encoding(self):
+        sample = "Hello world\n\u1234\u5678\u9abc"
+        for enc in ("utf-8", "utf-16"):
+            b = self.type2test(sample, enc)
+            self.assertEqual(b, self.type2test(sample.encode(enc)))
+        self.assertRaises(UnicodeEncodeError, self.type2test, sample, "latin-1")
+        b = self.type2test(sample, "latin-1", "ignore")
+        self.assertEqual(b, self.type2test(sample[:-3], "utf-8"))
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_decode(self):
+        sample = "Hello world\n\u1234\u5678\u9abc"
+        for enc in ("utf-8", "utf-16"):
+            b = self.type2test(sample, enc)
+            self.assertEqual(b.decode(enc), sample)
+        sample = "Hello world\n\x80\x81\xfe\xff"
+        b = self.type2test(sample, "latin-1")
+        self.assertRaises(UnicodeDecodeError, b.decode, "utf-8")
+        self.assertEqual(b.decode("utf-8", "ignore"), "Hello world\n")
+        self.assertEqual(b.decode(errors="ignore", encoding="utf-8"),
+                         "Hello world\n")
+        # Default encoding is utf-8
+        self.assertEqual(self.type2test(b'\xe2\x98\x83').decode(), '\u2603')
+
+    def test_from_int(self):
+        b = self.type2test(0)
+        self.assertEqual(b, self.type2test())
+        b = self.type2test(10)
+        self.assertEqual(b, self.type2test([0]*10))
+        b = self.type2test(10000)
+        self.assertEqual(b, self.type2test([0]*10000))
+
+    def test_concat(self):
+        b1 = self.type2test(b"abc")
+        b2 = self.type2test(b"def")
+        self.assertEqual(b1 + b2, b"abcdef")
+        self.assertEqual(b1 + bytes(b"def"), b"abcdef")
+        self.assertEqual(bytes(b"def") + b1, b"defabc")
+        self.assertRaises(TypeError, lambda: b1 + "def")
+        self.assertRaises(TypeError, lambda: "abc" + b2)
+
+    @unittest.skip("TODO: RUSTPYTHON")
+    def test_repeat(self):
+        for b in b"abc", self.type2test(b"abc"):
+            self.assertEqual(b * 3, b"abcabcabc")
+            self.assertEqual(b * 0, b"")
+            self.assertEqual(b * -1, b"")
+            self.assertRaises(TypeError, lambda: b * 3.14)
+            self.assertRaises(TypeError, lambda: 3.14 * b)
+            # XXX Shouldn't bytes and bytearray agree on what to raise?
+            with self.assertRaises((OverflowError, MemoryError)):
+                c = b * sys.maxsize
+            with self.assertRaises((OverflowError, MemoryError)):
+                b *= sys.maxsize
+
+    def test_repeat_1char(self):
+        self.assertEqual(self.type2test(b'x')*100, self.type2test([ord('x')]*100))
+
+    def test_contains(self):
+        b = self.type2test(b"abc")
+        self.assertIn(ord('a'), b)
+        self.assertIn(int(ord('a')), b)
+        self.assertNotIn(200, b)
+        self.assertRaises(ValueError, lambda: 300 in b)
+        self.assertRaises(ValueError, lambda: -1 in b)
+        self.assertRaises(ValueError, lambda: sys.maxsize+1 in b)
+        self.assertRaises(TypeError, lambda: None in b)
+        self.assertRaises(TypeError, lambda: float(ord('a')) in b)
+        self.assertRaises(TypeError, lambda: "a" in b)
+        for f in bytes, bytearray:
+            self.assertIn(f(b""), b)
+            self.assertIn(f(b"a"), b)
+            self.assertIn(f(b"b"), b)
+            self.assertIn(f(b"c"), b)
+            self.assertIn(f(b"ab"), b)
+            self.assertIn(f(b"bc"), b)
+            self.assertIn(f(b"abc"), b)
+            self.assertNotIn(f(b"ac"), b)
+            self.assertNotIn(f(b"d"), b)
+            self.assertNotIn(f(b"dab"), b)
+            self.assertNotIn(f(b"abd"), b)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_fromhex(self):
+        self.assertRaises(TypeError, self.type2test.fromhex)
+        self.assertRaises(TypeError, self.type2test.fromhex, 1)
+        self.assertEqual(self.type2test.fromhex(''), self.type2test())
+        b = bytearray([0x1a, 0x2b, 0x30])
+        self.assertEqual(self.type2test.fromhex('1a2B30'), b)
+        self.assertEqual(self.type2test.fromhex('  1A 2B  30   '), b)
+
+        # check that ASCII whitespace is ignored
+        self.assertEqual(self.type2test.fromhex(' 1A\n2B\t30\v'), b)
+        for c in "\x09\x0A\x0B\x0C\x0D\x20":
+            self.assertEqual(self.type2test.fromhex(c), self.type2test())
+        for c in "\x1C\x1D\x1E\x1F\x85\xa0\u2000\u2002\u2028":
+            self.assertRaises(ValueError, self.type2test.fromhex, c)
+
+        self.assertEqual(self.type2test.fromhex('0000'), b'\0\0')
+        self.assertRaises(TypeError, self.type2test.fromhex, b'1B')
+        self.assertRaises(ValueError, self.type2test.fromhex, 'a')
+        self.assertRaises(ValueError, self.type2test.fromhex, 'rt')
+        self.assertRaises(ValueError, self.type2test.fromhex, '1a b cd')
+        self.assertRaises(ValueError, self.type2test.fromhex, '\x00')
+        self.assertRaises(ValueError, self.type2test.fromhex, '12   \x00   34')
+
+        for data, pos in (
+            # invalid first hexadecimal character
+            ('12 x4 56', 3),
+            # invalid second hexadecimal character
+            ('12 3x 56', 4),
+            # two invalid hexadecimal characters
+            ('12 xy 56', 3),
+            # test non-ASCII string
+            ('12 3\xff 56', 4),
+        ):
+            with self.assertRaises(ValueError) as cm:
+                self.type2test.fromhex(data)
+            self.assertIn('at position %s' % pos, str(cm.exception))
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_hex(self):
+        self.assertRaises(TypeError, self.type2test.hex)
+        self.assertRaises(TypeError, self.type2test.hex, 1)
+        self.assertEqual(self.type2test(b"").hex(), "")
+        self.assertEqual(bytearray([0x1a, 0x2b, 0x30]).hex(), '1a2b30')
+        self.assertEqual(self.type2test(b"\x1a\x2b\x30").hex(), '1a2b30')
+        self.assertEqual(memoryview(b"\x1a\x2b\x30").hex(), '1a2b30')
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_hex_separator_basics(self):
+        three_bytes = self.type2test(b'\xb9\x01\xef')
+        self.assertEqual(three_bytes.hex(), 'b901ef')
+        with self.assertRaises(ValueError):
+            three_bytes.hex('')
+        with self.assertRaises(ValueError):
+            three_bytes.hex('xx')
+        self.assertEqual(three_bytes.hex(':', 0), 'b901ef')
+        with self.assertRaises(TypeError):
+            three_bytes.hex(None, 0)
+        with self.assertRaises(ValueError):
+            three_bytes.hex('\xff')
+        with self.assertRaises(ValueError):
+            three_bytes.hex(b'\xff')
+        with self.assertRaises(ValueError):
+            three_bytes.hex(b'\x80')
+        with self.assertRaises(ValueError):
+            three_bytes.hex(chr(0x100))
+        self.assertEqual(three_bytes.hex(':', 0), 'b901ef')
+        self.assertEqual(three_bytes.hex(b'\x00'), 'b9\x0001\x00ef')
+        self.assertEqual(three_bytes.hex('\x00'), 'b9\x0001\x00ef')
+        self.assertEqual(three_bytes.hex(b'\x7f'), 'b9\x7f01\x7fef')
+        self.assertEqual(three_bytes.hex('\x7f'), 'b9\x7f01\x7fef')
+        self.assertEqual(three_bytes.hex(':', 3), 'b901ef')
+        self.assertEqual(three_bytes.hex(':', 4), 'b901ef')
+        self.assertEqual(three_bytes.hex(':', -4), 'b901ef')
+        self.assertEqual(three_bytes.hex(':'), 'b9:01:ef')
+        self.assertEqual(three_bytes.hex(b'$'), 'b9$01$ef')
+        self.assertEqual(three_bytes.hex(':', 1), 'b9:01:ef')
+        self.assertEqual(three_bytes.hex(':', -1), 'b9:01:ef')
+        self.assertEqual(three_bytes.hex(':', 2), 'b9:01ef')
+        self.assertEqual(three_bytes.hex(':', 1), 'b9:01:ef')
+        self.assertEqual(three_bytes.hex('*', -2), 'b901*ef')
+
+        value = b'{s\005\000\000\000worldi\002\000\000\000s\005\000\000\000helloi\001\000\000\0000'
+        self.assertEqual(value.hex('.', 8), '7b7305000000776f.726c646902000000.730500000068656c.6c6f690100000030')
+
+    def test_hex_separator_five_bytes(self):
+        five_bytes = self.type2test(range(90,95))
+        self.assertEqual(five_bytes.hex(), '5a5b5c5d5e')
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_hex_separator_six_bytes(self):
+        six_bytes = self.type2test(x*3 for x in range(1, 7))
+        self.assertEqual(six_bytes.hex(), '0306090c0f12')
+        self.assertEqual(six_bytes.hex('.', 1), '03.06.09.0c.0f.12')
+        self.assertEqual(six_bytes.hex(' ', 2), '0306 090c 0f12')
+        self.assertEqual(six_bytes.hex('-', 3), '030609-0c0f12')
+        self.assertEqual(six_bytes.hex(':', 4), '0306:090c0f12')
+        self.assertEqual(six_bytes.hex(':', 5), '03:06090c0f12')
+        self.assertEqual(six_bytes.hex(':', 6), '0306090c0f12')
+        self.assertEqual(six_bytes.hex(':', 95), '0306090c0f12')
+        self.assertEqual(six_bytes.hex('_', -3), '030609_0c0f12')
+        self.assertEqual(six_bytes.hex(':', -4), '0306090c:0f12')
+        self.assertEqual(six_bytes.hex(b'@', -5), '0306090c0f@12')
+        self.assertEqual(six_bytes.hex(':', -6), '0306090c0f12')
+        self.assertEqual(six_bytes.hex(' ', -95), '0306090c0f12')
+
+    def test_join(self):
+        self.assertEqual(self.type2test(b"").join([]), b"")
+        self.assertEqual(self.type2test(b"").join([b""]), b"")
+        for lst in [[b"abc"], [b"a", b"bc"], [b"ab", b"c"], [b"a", b"b", b"c"]]:
+            lst = list(map(self.type2test, lst))
+            self.assertEqual(self.type2test(b"").join(lst), b"abc")
+            self.assertEqual(self.type2test(b"").join(tuple(lst)), b"abc")
+            self.assertEqual(self.type2test(b"").join(iter(lst)), b"abc")
+        dot_join = self.type2test(b".:").join
+        self.assertEqual(dot_join([b"ab", b"cd"]), b"ab.:cd")
+        self.assertEqual(dot_join([memoryview(b"ab"), b"cd"]), b"ab.:cd")
+        self.assertEqual(dot_join([b"ab", memoryview(b"cd")]), b"ab.:cd")
+        self.assertEqual(dot_join([bytearray(b"ab"), b"cd"]), b"ab.:cd")
+        self.assertEqual(dot_join([b"ab", bytearray(b"cd")]), b"ab.:cd")
+        # Stress it with many items
+        seq = [b"abc"] * 1000
+        expected = b"abc" + b".:abc" * 999
+        self.assertEqual(dot_join(seq), expected)
+        self.assertRaises(TypeError, self.type2test(b" ").join, None)
+        # Error handling and cleanup when some item in the middle of the
+        # sequence has the wrong type.
+        with self.assertRaises(TypeError):
+            dot_join([bytearray(b"ab"), "cd", b"ef"])
+        with self.assertRaises(TypeError):
+            dot_join([memoryview(b"ab"), "cd", b"ef"])
+
+    def test_count(self):
+        b = self.type2test(b'mississippi')
+        i = 105
+        p = 112
+        w = 119
+
+        self.assertEqual(b.count(b'i'), 4)
+        self.assertEqual(b.count(b'ss'), 2)
+        self.assertEqual(b.count(b'w'), 0)
+
+        self.assertEqual(b.count(i), 4)
+        self.assertEqual(b.count(w), 0)
+
+        self.assertEqual(b.count(b'i', 6), 2)
+        self.assertEqual(b.count(b'p', 6), 2)
+        self.assertEqual(b.count(b'i', 1, 3), 1)
+        self.assertEqual(b.count(b'p', 7, 9), 1)
+
+        self.assertEqual(b.count(i, 6), 2)
+        self.assertEqual(b.count(p, 6), 2)
+        self.assertEqual(b.count(i, 1, 3), 1)
+        self.assertEqual(b.count(p, 7, 9), 1)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_startswith(self):
+        b = self.type2test(b'hello')
+        self.assertFalse(self.type2test().startswith(b"anything"))
+        self.assertTrue(b.startswith(b"hello"))
+        self.assertTrue(b.startswith(b"hel"))
+        self.assertTrue(b.startswith(b"h"))
+        self.assertFalse(b.startswith(b"hellow"))
+        self.assertFalse(b.startswith(b"ha"))
+        with self.assertRaises(TypeError) as cm:
+            b.startswith([b'h'])
+        exc = str(cm.exception)
+        self.assertIn('bytes', exc)
+        self.assertIn('tuple', exc)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_endswith(self):
+        b = self.type2test(b'hello')
+        self.assertFalse(bytearray().endswith(b"anything"))
+        self.assertTrue(b.endswith(b"hello"))
+        self.assertTrue(b.endswith(b"llo"))
+        self.assertTrue(b.endswith(b"o"))
+        self.assertFalse(b.endswith(b"whello"))
+        self.assertFalse(b.endswith(b"no"))
+        with self.assertRaises(TypeError) as cm:
+            b.endswith([b'o'])
+        exc = str(cm.exception)
+        self.assertIn('bytes', exc)
+        self.assertIn('tuple', exc)
+
+    def test_find(self):
+        b = self.type2test(b'mississippi')
+        i = 105
+        w = 119
+
+        self.assertEqual(b.find(b'ss'), 2)
+        self.assertEqual(b.find(b'w'), -1)
+        self.assertEqual(b.find(b'mississippian'), -1)
+
+        self.assertEqual(b.find(i), 1)
+        self.assertEqual(b.find(w), -1)
+
+        self.assertEqual(b.find(b'ss', 3), 5)
+        self.assertEqual(b.find(b'ss', 1, 7), 2)
+        self.assertEqual(b.find(b'ss', 1, 3), -1)
+
+        self.assertEqual(b.find(i, 6), 7)
+        self.assertEqual(b.find(i, 1, 3), 1)
+        self.assertEqual(b.find(w, 1, 3), -1)
+
+        for index in (-1, 256, sys.maxsize + 1):
+            self.assertRaisesRegex(
+                ValueError, r'byte must be in range\(0, 256\)',
+                b.find, index)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_rfind(self):
+        b = self.type2test(b'mississippi')
+        i = 105
+        w = 119
+
+        self.assertEqual(b.rfind(b'ss'), 5)
+        self.assertEqual(b.rfind(b'w'), -1)
+        self.assertEqual(b.rfind(b'mississippian'), -1)
+
+        self.assertEqual(b.rfind(i), 10)
+        self.assertEqual(b.rfind(w), -1)
+
+        self.assertEqual(b.rfind(b'ss', 3), 5)
+        self.assertEqual(b.rfind(b'ss', 0, 6), 2)
+
+        self.assertEqual(b.rfind(i, 1, 3), 1)
+        self.assertEqual(b.rfind(i, 3, 9), 7)
+        self.assertEqual(b.rfind(w, 1, 3), -1)
+
+    def test_index(self):
+        b = self.type2test(b'mississippi')
+        i = 105
+        w = 119
+
+        self.assertEqual(b.index(b'ss'), 2)
+        self.assertRaises(ValueError, b.index, b'w')
+        self.assertRaises(ValueError, b.index, b'mississippian')
+
+        self.assertEqual(b.index(i), 1)
+        self.assertRaises(ValueError, b.index, w)
+
+        self.assertEqual(b.index(b'ss', 3), 5)
+        self.assertEqual(b.index(b'ss', 1, 7), 2)
+        self.assertRaises(ValueError, b.index, b'ss', 1, 3)
+
+        self.assertEqual(b.index(i, 6), 7)
+        self.assertEqual(b.index(i, 1, 3), 1)
+        self.assertRaises(ValueError, b.index, w, 1, 3)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_rindex(self):
+        b = self.type2test(b'mississippi')
+        i = 105
+        w = 119
+
+        self.assertEqual(b.rindex(b'ss'), 5)
+        self.assertRaises(ValueError, b.rindex, b'w')
+        self.assertRaises(ValueError, b.rindex, b'mississippian')
+
+        self.assertEqual(b.rindex(i), 10)
+        self.assertRaises(ValueError, b.rindex, w)
+
+        self.assertEqual(b.rindex(b'ss', 3), 5)
+        self.assertEqual(b.rindex(b'ss', 0, 6), 2)
+
+        self.assertEqual(b.rindex(i, 1, 3), 1)
+        self.assertEqual(b.rindex(i, 3, 9), 7)
+        self.assertRaises(ValueError, b.rindex, w, 1, 3)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_mod(self):
+        b = self.type2test(b'hello, %b!')
+        orig = b
+        b = b % b'world'
+        self.assertEqual(b, b'hello, world!')
+        self.assertEqual(orig, b'hello, %b!')
+        self.assertFalse(b is orig)
+        b = self.type2test(b'%s / 100 = %d%%')
+        a = b % (b'seventy-nine', 79)
+        self.assertEqual(a, b'seventy-nine / 100 = 79%')
+        self.assertIs(type(a), self.type2test)
+        # issue 29714
+        b = self.type2test(b'hello,\x00%b!')
+        b = b % b'world'
+        self.assertEqual(b, b'hello,\x00world!')
+        self.assertIs(type(b), self.type2test)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_imod(self):
+        b = self.type2test(b'hello, %b!')
+        orig = b
+        b %= b'world'
+        self.assertEqual(b, b'hello, world!')
+        self.assertEqual(orig, b'hello, %b!')
+        self.assertFalse(b is orig)
+        b = self.type2test(b'%s / 100 = %d%%')
+        b %= (b'seventy-nine', 79)
+        self.assertEqual(b, b'seventy-nine / 100 = 79%')
+        self.assertIs(type(b), self.type2test)
+        # issue 29714
+        b = self.type2test(b'hello,\x00%b!')
+        b %= b'world'
+        self.assertEqual(b, b'hello,\x00world!')
+        self.assertIs(type(b), self.type2test)
+
+    def test_rmod(self):
+        with self.assertRaises(TypeError):
+            object() % self.type2test(b'abc')
+        self.assertIs(self.type2test(b'abc').__rmod__('%r'), NotImplemented)
+
+    def test_replace(self):
+        b = self.type2test(b'mississippi')
+        self.assertEqual(b.replace(b'i', b'a'), b'massassappa')
+        self.assertEqual(b.replace(b'ss', b'x'), b'mixixippi')
+
+    def test_replace_int_error(self):
+        self.assertRaises(TypeError, self.type2test(b'a b').replace, 32, b'')
+
+    def test_split_string_error(self):
+        self.assertRaises(TypeError, self.type2test(b'a b').split, ' ')
+        self.assertRaises(TypeError, self.type2test(b'a b').rsplit, ' ')
+
+    def test_split_int_error(self):
+        self.assertRaises(TypeError, self.type2test(b'a b').split, 32)
+        self.assertRaises(TypeError, self.type2test(b'a b').rsplit, 32)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_split_unicodewhitespace(self):
+        for b in (b'a\x1Cb', b'a\x1Db', b'a\x1Eb', b'a\x1Fb'):
+            b = self.type2test(b)
+            self.assertEqual(b.split(), [b])
+        b = self.type2test(b"\x09\x0A\x0B\x0C\x0D\x1C\x1D\x1E\x1F")
+        self.assertEqual(b.split(), [b'\x1c\x1d\x1e\x1f'])
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_rsplit_unicodewhitespace(self):
+        b = self.type2test(b"\x09\x0A\x0B\x0C\x0D\x1C\x1D\x1E\x1F")
+        self.assertEqual(b.rsplit(), [b'\x1c\x1d\x1e\x1f'])
+
+    @unittest.skip("TODO: RUSTPYTHON")
+    def test_partition(self):
+        b = self.type2test(b'mississippi')
+        self.assertEqual(b.partition(b'ss'), (b'mi', b'ss', b'issippi'))
+        self.assertEqual(b.partition(b'w'), (b'mississippi', b'', b''))
+
+    @unittest.skip("TODO: RUSTPYTHON")
+    def test_rpartition(self):
+        b = self.type2test(b'mississippi')
+        self.assertEqual(b.rpartition(b'ss'), (b'missi', b'ss', b'ippi'))
+        self.assertEqual(b.rpartition(b'i'), (b'mississipp', b'i', b''))
+        self.assertEqual(b.rpartition(b'w'), (b'', b'', b'mississippi'))
+
+    def test_partition_string_error(self):
+        self.assertRaises(TypeError, self.type2test(b'a b').partition, ' ')
+        self.assertRaises(TypeError, self.type2test(b'a b').rpartition, ' ')
+
+    def test_partition_int_error(self):
+        self.assertRaises(TypeError, self.type2test(b'a b').partition, 32)
+        self.assertRaises(TypeError, self.type2test(b'a b').rpartition, 32)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_pickling(self):
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            for b in b"", b"a", b"abc", b"\xffab\x80", b"\0\0\377\0\0":
+                b = self.type2test(b)
+                ps = pickle.dumps(b, proto)
+                q = pickle.loads(ps)
+                self.assertEqual(b, q)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_iterator_pickling(self):
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            for b in b"", b"a", b"abc", b"\xffab\x80", b"\0\0\377\0\0":
+                it = itorg = iter(self.type2test(b))
+                data = list(self.type2test(b))
+                d = pickle.dumps(it, proto)
+                it = pickle.loads(d)
+                self.assertEqual(type(itorg), type(it))
+                self.assertEqual(list(it), data)
+
+                it = pickle.loads(d)
+                if not b:
+                    continue
+                next(it)
+                d = pickle.dumps(it, proto)
+                it = pickle.loads(d)
+                self.assertEqual(list(it), data[1:])
+
+    def test_strip_bytearray(self):
+        self.assertEqual(self.type2test(b'abc').strip(memoryview(b'ac')), b'b')
+        self.assertEqual(self.type2test(b'abc').lstrip(memoryview(b'ac')), b'bc')
+        self.assertEqual(self.type2test(b'abc').rstrip(memoryview(b'ac')), b'ab')
+
+    def test_strip_string_error(self):
+        self.assertRaises(TypeError, self.type2test(b'abc').strip, 'ac')
+        self.assertRaises(TypeError, self.type2test(b'abc').lstrip, 'ac')
+        self.assertRaises(TypeError, self.type2test(b'abc').rstrip, 'ac')
+
+    def test_strip_int_error(self):
+        self.assertRaises(TypeError, self.type2test(b' abc ').strip, 32)
+        self.assertRaises(TypeError, self.type2test(b' abc ').lstrip, 32)
+        self.assertRaises(TypeError, self.type2test(b' abc ').rstrip, 32)
+
+    def test_center(self):
+        # Fill character can be either bytes or bytearray (issue 12380)
+        b = self.type2test(b'abc')
+        for fill_type in (bytes, bytearray):
+            self.assertEqual(b.center(7, fill_type(b'-')),
+                             self.type2test(b'--abc--'))
+
+    def test_ljust(self):
+        # Fill character can be either bytes or bytearray (issue 12380)
+        b = self.type2test(b'abc')
+        for fill_type in (bytes, bytearray):
+            self.assertEqual(b.ljust(7, fill_type(b'-')),
+                             self.type2test(b'abc----'))
+
+    def test_rjust(self):
+        # Fill character can be either bytes or bytearray (issue 12380)
+        b = self.type2test(b'abc')
+        for fill_type in (bytes, bytearray):
+            self.assertEqual(b.rjust(7, fill_type(b'-')),
+                             self.type2test(b'----abc'))
+
+    def test_xjust_int_error(self):
+        self.assertRaises(TypeError, self.type2test(b'abc').center, 7, 32)
+        self.assertRaises(TypeError, self.type2test(b'abc').ljust, 7, 32)
+        self.assertRaises(TypeError, self.type2test(b'abc').rjust, 7, 32)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_ord(self):
+        b = self.type2test(b'\0A\x7f\x80\xff')
+        self.assertEqual([ord(b[i:i+1]) for i in range(len(b))],
+                         [0, 65, 127, 128, 255])
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_maketrans(self):
+        transtable = b'\000\001\002\003\004\005\006\007\010\011\012\013\014\015\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037 !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`xyzdefghijklmnopqrstuvwxyz{|}~\177\200\201\202\203\204\205\206\207\210\211\212\213\214\215\216\217\220\221\222\223\224\225\226\227\230\231\232\233\234\235\236\237\240\241\242\243\244\245\246\247\250\251\252\253\254\255\256\257\260\261\262\263\264\265\266\267\270\271\272\273\274\275\276\277\300\301\302\303\304\305\306\307\310\311\312\313\314\315\316\317\320\321\322\323\324\325\326\327\330\331\332\333\334\335\336\337\340\341\342\343\344\345\346\347\350\351\352\353\354\355\356\357\360\361\362\363\364\365\366\367\370\371\372\373\374\375\376\377'
+        self.assertEqual(self.type2test.maketrans(b'abc', b'xyz'), transtable)
+        transtable = b'\000\001\002\003\004\005\006\007\010\011\012\013\014\015\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037 !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\177\200\201\202\203\204\205\206\207\210\211\212\213\214\215\216\217\220\221\222\223\224\225\226\227\230\231\232\233\234\235\236\237\240\241\242\243\244\245\246\247\250\251\252\253\254\255\256\257\260\261\262\263\264\265\266\267\270\271\272\273\274\275\276\277\300\301\302\303\304\305\306\307\310\311\312\313\314\315\316\317\320\321\322\323\324\325\326\327\330\331\332\333\334\335\336\337\340\341\342\343\344\345\346\347\350\351\352\353\354\355\356\357\360\361\362\363\364\365\366\367\370\371\372\373\374xyz'
+        self.assertEqual(self.type2test.maketrans(b'\375\376\377', b'xyz'), transtable)
+        self.assertRaises(ValueError, self.type2test.maketrans, b'abc', b'xyzq')
+        self.assertRaises(TypeError, self.type2test.maketrans, 'abc', 'def')
+
+    @unittest.skip("TODO: RUSTPYTHON")
+    def test_none_arguments(self):
+        # issue 11828
+        b = self.type2test(b'hello')
+        l = self.type2test(b'l')
+        h = self.type2test(b'h')
+        x = self.type2test(b'x')
+        o = self.type2test(b'o')
+
+        self.assertEqual(2, b.find(l, None))
+        self.assertEqual(3, b.find(l, -2, None))
+        self.assertEqual(2, b.find(l, None, -2))
+        self.assertEqual(0, b.find(h, None, None))
+
+        self.assertEqual(3, b.rfind(l, None))
+        self.assertEqual(3, b.rfind(l, -2, None))
+        self.assertEqual(2, b.rfind(l, None, -2))
+        self.assertEqual(0, b.rfind(h, None, None))
+
+        self.assertEqual(2, b.index(l, None))
+        self.assertEqual(3, b.index(l, -2, None))
+        self.assertEqual(2, b.index(l, None, -2))
+        self.assertEqual(0, b.index(h, None, None))
+
+        self.assertEqual(3, b.rindex(l, None))
+        self.assertEqual(3, b.rindex(l, -2, None))
+        self.assertEqual(2, b.rindex(l, None, -2))
+        self.assertEqual(0, b.rindex(h, None, None))
+
+        self.assertEqual(2, b.count(l, None))
+        self.assertEqual(1, b.count(l, -2, None))
+        self.assertEqual(1, b.count(l, None, -2))
+        self.assertEqual(0, b.count(x, None, None))
+
+        self.assertEqual(True, b.endswith(o, None))
+        self.assertEqual(True, b.endswith(o, -2, None))
+        self.assertEqual(True, b.endswith(l, None, -2))
+        self.assertEqual(False, b.endswith(x, None, None))
+
+        self.assertEqual(True, b.startswith(h, None))
+        self.assertEqual(True, b.startswith(l, -2, None))
+        self.assertEqual(True, b.startswith(h, None, -2))
+        self.assertEqual(False, b.startswith(x, None, None))
+
+    def test_integer_arguments_out_of_byte_range(self):
+        b = self.type2test(b'hello')
+
+        for method in (b.count, b.find, b.index, b.rfind, b.rindex):
+            self.assertRaises(ValueError, method, -1)
+            self.assertRaises(ValueError, method, 256)
+            self.assertRaises(ValueError, method, 9999)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_find_etc_raise_correct_error_messages(self):
+        # issue 11828
+        b = self.type2test(b'hello')
+        x = self.type2test(b'x')
+        self.assertRaisesRegex(TypeError, r'\bfind\b', b.find,
+                                x, None, None, None)
+        self.assertRaisesRegex(TypeError, r'\brfind\b', b.rfind,
+                                x, None, None, None)
+        self.assertRaisesRegex(TypeError, r'\bindex\b', b.index,
+                                x, None, None, None)
+        self.assertRaisesRegex(TypeError, r'\brindex\b', b.rindex,
+                                x, None, None, None)
+        self.assertRaisesRegex(TypeError, r'\bcount\b', b.count,
+                                x, None, None, None)
+        self.assertRaisesRegex(TypeError, r'\bstartswith\b', b.startswith,
+                                x, None, None, None)
+        self.assertRaisesRegex(TypeError, r'\bendswith\b', b.endswith,
+                                x, None, None, None)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_free_after_iterating(self):
+        test.support.check_free_after_iterating(self, iter, self.type2test)
+        test.support.check_free_after_iterating(self, reversed, self.type2test)
+
+    def test_translate(self):
+        b = self.type2test(b'hello')
+        rosetta = bytearray(range(256))
+        rosetta[ord('o')] = ord('e')
+
+        self.assertRaises(TypeError, b.translate)
+        self.assertRaises(TypeError, b.translate, None, None)
+        self.assertRaises(ValueError, b.translate, bytes(range(255)))
+
+        c = b.translate(rosetta, b'hello')
+        self.assertEqual(b, b'hello')
+        self.assertIsInstance(c, self.type2test)
+
+        c = b.translate(rosetta)
+        d = b.translate(rosetta, b'')
+        self.assertEqual(c, d)
+        self.assertEqual(c, b'helle')
+
+        c = b.translate(rosetta, b'l')
+        self.assertEqual(c, b'hee')
+        c = b.translate(None, b'e')
+        self.assertEqual(c, b'hllo')
+
+        # test delete as a keyword argument
+        c = b.translate(rosetta, delete=b'')
+        self.assertEqual(c, b'helle')
+        c = b.translate(rosetta, delete=b'l')
+        self.assertEqual(c, b'hee')
+        c = b.translate(None, delete=b'e')
+        self.assertEqual(c, b'hllo')
+
+
+class BytesTest(BaseBytesTest, unittest.TestCase):
+    type2test = bytes
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_getitem_error(self):
+        b = b'python'
+        msg = "byte indices must be integers or slices"
+        with self.assertRaisesRegex(TypeError, msg):
+            b['a']
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_buffer_is_readonly(self):
+        fd = os.open(__file__, os.O_RDONLY)
+        with open(fd, "rb", buffering=0) as f:
+            self.assertRaises(TypeError, f.readinto, b"")
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_custom(self):
+        class A:
+            def __bytes__(self):
+                return b'abc'
+        self.assertEqual(bytes(A()), b'abc')
+        class A: pass
+        self.assertRaises(TypeError, bytes, A())
+        class A:
+            def __bytes__(self):
+                return None
+        self.assertRaises(TypeError, bytes, A())
+        class A:
+            def __bytes__(self):
+                return b'a'
+            def __index__(self):
+                return 42
+        self.assertEqual(bytes(A()), b'a')
+        # Issue #25766
+        class A(str):
+            def __bytes__(self):
+                return b'abc'
+        self.assertEqual(bytes(A('\u20ac')), b'abc')
+        self.assertEqual(bytes(A('\u20ac'), 'iso8859-15'), b'\xa4')
+        # Issue #24731
+        class A:
+            def __bytes__(self):
+                return OtherBytesSubclass(b'abc')
+        self.assertEqual(bytes(A()), b'abc')
+        self.assertIs(type(bytes(A())), OtherBytesSubclass)
+        self.assertEqual(BytesSubclass(A()), b'abc')
+        self.assertIs(type(BytesSubclass(A())), BytesSubclass)
+
+    # Test PyBytes_FromFormat()
+    def test_from_format(self):
+        ctypes = test.support.import_module('ctypes')
+        _testcapi = test.support.import_module('_testcapi')
+        from ctypes import pythonapi, py_object
+        from ctypes import (
+            c_int, c_uint,
+            c_long, c_ulong,
+            c_size_t, c_ssize_t,
+            c_char_p)
+
+        PyBytes_FromFormat = pythonapi.PyBytes_FromFormat
+        PyBytes_FromFormat.restype = py_object
+
+        # basic tests
+        self.assertEqual(PyBytes_FromFormat(b'format'),
+                         b'format')
+        self.assertEqual(PyBytes_FromFormat(b'Hello %s !', b'world'),
+                         b'Hello world !')
+
+        # test formatters
+        self.assertEqual(PyBytes_FromFormat(b'c=%c', c_int(0)),
+                         b'c=\0')
+        self.assertEqual(PyBytes_FromFormat(b'c=%c', c_int(ord('@'))),
+                         b'c=@')
+        self.assertEqual(PyBytes_FromFormat(b'c=%c', c_int(255)),
+                         b'c=\xff')
+        self.assertEqual(PyBytes_FromFormat(b'd=%d ld=%ld zd=%zd',
+                                            c_int(1), c_long(2),
+                                            c_size_t(3)),
+                         b'd=1 ld=2 zd=3')
+        self.assertEqual(PyBytes_FromFormat(b'd=%d ld=%ld zd=%zd',
+                                            c_int(-1), c_long(-2),
+                                            c_size_t(-3)),
+                         b'd=-1 ld=-2 zd=-3')
+        self.assertEqual(PyBytes_FromFormat(b'u=%u lu=%lu zu=%zu',
+                                            c_uint(123), c_ulong(456),
+                                            c_size_t(789)),
+                         b'u=123 lu=456 zu=789')
+        self.assertEqual(PyBytes_FromFormat(b'i=%i', c_int(123)),
+                         b'i=123')
+        self.assertEqual(PyBytes_FromFormat(b'i=%i', c_int(-123)),
+                         b'i=-123')
+        self.assertEqual(PyBytes_FromFormat(b'x=%x', c_int(0xabc)),
+                         b'x=abc')
+
+        sizeof_ptr = ctypes.sizeof(c_char_p)
+
+        if os.name == 'nt':
+            # Windows (MSCRT)
+            ptr_format = '0x%0{}X'.format(2 * sizeof_ptr)
+            def ptr_formatter(ptr):
+                return (ptr_format % ptr)
+        else:
+            # UNIX (glibc)
+            def ptr_formatter(ptr):
+                return '%#x' % ptr
+
+        ptr = 0xabcdef
+        self.assertEqual(PyBytes_FromFormat(b'ptr=%p', c_char_p(ptr)),
+                         ('ptr=' + ptr_formatter(ptr)).encode('ascii'))
+        self.assertEqual(PyBytes_FromFormat(b's=%s', c_char_p(b'cstr')),
+                         b's=cstr')
+
+        # test minimum and maximum integer values
+        size_max = c_size_t(-1).value
+        for formatstr, ctypes_type, value, py_formatter in (
+            (b'%d', c_int, _testcapi.INT_MIN, str),
+            (b'%d', c_int, _testcapi.INT_MAX, str),
+            (b'%ld', c_long, _testcapi.LONG_MIN, str),
+            (b'%ld', c_long, _testcapi.LONG_MAX, str),
+            (b'%lu', c_ulong, _testcapi.ULONG_MAX, str),
+            (b'%zd', c_ssize_t, _testcapi.PY_SSIZE_T_MIN, str),
+            (b'%zd', c_ssize_t, _testcapi.PY_SSIZE_T_MAX, str),
+            (b'%zu', c_size_t, size_max, str),
+            (b'%p', c_char_p, size_max, ptr_formatter),
+        ):
+            self.assertEqual(PyBytes_FromFormat(formatstr, ctypes_type(value)),
+                             py_formatter(value).encode('ascii')),
+
+        # width and precision (width is currently ignored)
+        self.assertEqual(PyBytes_FromFormat(b'%5s', b'a'),
+                         b'a')
+        self.assertEqual(PyBytes_FromFormat(b'%.3s', b'abcdef'),
+                         b'abc')
+
+        # '%%' formatter
+        self.assertEqual(PyBytes_FromFormat(b'%%'),
+                         b'%')
+        self.assertEqual(PyBytes_FromFormat(b'[%%]'),
+                         b'[%]')
+        self.assertEqual(PyBytes_FromFormat(b'%%%c', c_int(ord('_'))),
+                         b'%_')
+        self.assertEqual(PyBytes_FromFormat(b'%%s'),
+                         b'%s')
+
+        # Invalid formats and partial formatting
+        self.assertEqual(PyBytes_FromFormat(b'%'), b'%')
+        self.assertEqual(PyBytes_FromFormat(b'x=%i y=%', c_int(2), c_int(3)),
+                         b'x=2 y=%')
+
+        # Issue #19969: %c must raise OverflowError for values
+        # not in the range [0; 255]
+        self.assertRaises(OverflowError,
+                          PyBytes_FromFormat, b'%c', c_int(-1))
+        self.assertRaises(OverflowError,
+                          PyBytes_FromFormat, b'%c', c_int(256))
+
+        # Issue #33817: empty strings
+        self.assertEqual(PyBytes_FromFormat(b''),
+                         b'')
+        self.assertEqual(PyBytes_FromFormat(b'%s', b''),
+                         b'')
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_bytes_blocking(self):
+        class IterationBlocked(list):
+            __bytes__ = None
+        i = [0, 1, 2, 3]
+        self.assertEqual(bytes(i), b'\x00\x01\x02\x03')
+        self.assertRaises(TypeError, bytes, IterationBlocked(i))
+
+        # At least in CPython, because bytes.__new__ and the C API
+        # PyBytes_FromObject have different fallback rules, integer
+        # fallback is handled specially, so test separately.
+        class IntBlocked(int):
+            __bytes__ = None
+        self.assertEqual(bytes(3), b'\0\0\0')
+        self.assertRaises(TypeError, bytes, IntBlocked(3))
+
+        # While there is no separately-defined rule for handling bytes
+        # subclasses differently from other buffer-interface classes,
+        # an implementation may well special-case them (as CPython 2.x
+        # str did), so test them separately.
+        class BytesSubclassBlocked(bytes):
+            __bytes__ = None
+        self.assertEqual(bytes(b'ab'), b'ab')
+        self.assertRaises(TypeError, bytes, BytesSubclassBlocked(b'ab'))
+
+        class BufferBlocked(bytearray):
+            __bytes__ = None
+        ba, bb = bytearray(b'ab'), BufferBlocked(b'ab')
+        self.assertEqual(bytes(ba), b'ab')
+        self.assertRaises(TypeError, bytes, bb)
+
+
+class ByteArrayTest(BaseBytesTest, unittest.TestCase):
+    type2test = bytearray
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_getitem_error(self):
+        b = bytearray(b'python')
+        msg = "bytearray indices must be integers or slices"
+        with self.assertRaisesRegex(TypeError, msg):
+            b['a']
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_setitem_error(self):
+        b = bytearray(b'python')
+        msg = "bytearray indices must be integers or slices"
+        with self.assertRaisesRegex(TypeError, msg):
+            b['a'] = "python"
+
+    def test_nohash(self):
+        self.assertRaises(TypeError, hash, bytearray())
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_bytearray_api(self):
+        short_sample = b"Hello world\n"
+        sample = short_sample + b"\0"*(20 - len(short_sample))
+        tfn = tempfile.mktemp()
+        try:
+            # Prepare
+            with open(tfn, "wb") as f:
+                f.write(short_sample)
+            # Test readinto
+            with open(tfn, "rb") as f:
+                b = bytearray(20)
+                n = f.readinto(b)
+            self.assertEqual(n, len(short_sample))
+            self.assertEqual(list(b), list(sample))
+            # Test writing in binary mode
+            with open(tfn, "wb") as f:
+                f.write(b)
+            with open(tfn, "rb") as f:
+                self.assertEqual(f.read(), sample)
+            # Text mode is ambiguous; don't test
+        finally:
+            try:
+                os.remove(tfn)
+            except OSError:
+                pass
+
+    def test_reverse(self):
+        b = bytearray(b'hello')
+        self.assertEqual(b.reverse(), None)
+        self.assertEqual(b, b'olleh')
+        b = bytearray(b'hello1') # test even number of items
+        b.reverse()
+        self.assertEqual(b, b'1olleh')
+        b = bytearray()
+        b.reverse()
+        self.assertFalse(b)
+
+    def test_clear(self):
+        b = bytearray(b'python')
+        b.clear()
+        self.assertEqual(b, b'')
+
+        b = bytearray(b'')
+        b.clear()
+        self.assertEqual(b, b'')
+
+        b = bytearray(b'')
+        b.append(ord('r'))
+        b.clear()
+        b.append(ord('p'))
+        self.assertEqual(b, b'p')
+
+    def test_copy(self):
+        b = bytearray(b'abc')
+        bb = b.copy()
+        self.assertEqual(bb, b'abc')
+
+        b = bytearray(b'')
+        bb = b.copy()
+        self.assertEqual(bb, b'')
+
+        # test that it's indeed a copy and not a reference
+        b = bytearray(b'abc')
+        bb = b.copy()
+        self.assertEqual(b, bb)
+        self.assertIsNot(b, bb)
+        bb.append(ord('d'))
+        self.assertEqual(bb, b'abcd')
+        self.assertEqual(b, b'abc')
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_regexps(self):
+        def by(s):
+            return bytearray(map(ord, s))
+        b = by("Hello, world")
+        self.assertEqual(re.findall(br"\w+", b), [by("Hello"), by("world")])
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_setitem(self):
+        b = bytearray([1, 2, 3])
+        b[1] = 100
+        self.assertEqual(b, bytearray([1, 100, 3]))
+        b[-1] = 200
+        self.assertEqual(b, bytearray([1, 100, 200]))
+        b[0] = Indexable(10)
+        self.assertEqual(b, bytearray([10, 100, 200]))
+        try:
+            b[3] = 0
+            self.fail("Didn't raise IndexError")
+        except IndexError:
+            pass
+        try:
+            b[-10] = 0
+            self.fail("Didn't raise IndexError")
+        except IndexError:
+            pass
+        try:
+            b[0] = 256
+            self.fail("Didn't raise ValueError")
+        except ValueError:
+            pass
+        try:
+            b[0] = Indexable(-1)
+            self.fail("Didn't raise ValueError")
+        except ValueError:
+            pass
+        try:
+            b[0] = None
+            self.fail("Didn't raise TypeError")
+        except TypeError:
+            pass
+
+    def test_delitem(self):
+        b = bytearray(range(10))
+        del b[0]
+        self.assertEqual(b, bytearray(range(1, 10)))
+        del b[-1]
+        self.assertEqual(b, bytearray(range(1, 9)))
+        del b[4]
+        self.assertEqual(b, bytearray([1, 2, 3, 4, 6, 7, 8]))
+
+    @unittest.skip("TODO: RUSTPYTHON")
+    def test_setslice(self):
+        b = bytearray(range(10))
+        self.assertEqual(list(b), list(range(10)))
+
+        b[0:5] = bytearray([1, 1, 1, 1, 1])
+        self.assertEqual(b, bytearray([1, 1, 1, 1, 1, 5, 6, 7, 8, 9]))
+
+        del b[0:-5]
+        self.assertEqual(b, bytearray([5, 6, 7, 8, 9]))
+
+        b[0:0] = bytearray([0, 1, 2, 3, 4])
+        self.assertEqual(b, bytearray(range(10)))
+
+        b[-7:-3] = bytearray([100, 101])
+        self.assertEqual(b, bytearray([0, 1, 2, 100, 101, 7, 8, 9]))
+
+        b[3:5] = [3, 4, 5, 6]
+        self.assertEqual(b, bytearray(range(10)))
+
+        b[3:0] = [42, 42, 42]
+        self.assertEqual(b, bytearray([0, 1, 2, 42, 42, 42, 3, 4, 5, 6, 7, 8, 9]))
+
+        b[3:] = b'foo'
+        self.assertEqual(b, bytearray([0, 1, 2, 102, 111, 111]))
+
+        b[:3] = memoryview(b'foo')
+        self.assertEqual(b, bytearray([102, 111, 111, 102, 111, 111]))
+
+        b[3:4] = []
+        self.assertEqual(b, bytearray([102, 111, 111, 111, 111]))
+
+        for elem in [5, -5, 0, int(10e20), 'str', 2.3,
+                     ['a', 'b'], [b'a', b'b'], [[]]]:
+            with self.assertRaises(TypeError):
+                b[3:4] = elem
+
+        for elem in [[254, 255, 256], [-256, 9000]]:
+            with self.assertRaises(ValueError):
+                b[3:4] = elem
+
+    def test_setslice_extend(self):
+        # Exercise the resizing logic (see issue #19087)
+        b = bytearray(range(100))
+        self.assertEqual(list(b), list(range(100)))
+        del b[:10]
+        self.assertEqual(list(b), list(range(10, 100)))
+        b.extend(range(100, 110))
+        self.assertEqual(list(b), list(range(10, 110)))
+
+    def test_fifo_overrun(self):
+        # Test for issue #23985, a buffer overrun when implementing a FIFO
+        # Build Python in pydebug mode for best results.
+        b = bytearray(10)
+        b.pop()        # Defeat expanding buffer off-by-one quirk
+        del b[:1]      # Advance start pointer without reallocating
+        b += bytes(2)  # Append exactly the number of deleted bytes
+        del b          # Free memory buffer, allowing pydebug verification
+
+    def test_del_expand(self):
+        # Reducing the size should not expand the buffer (issue #23985)
+        b = bytearray(10)
+        size = sys.getsizeof(b)
+        del b[:1]
+        self.assertLessEqual(sys.getsizeof(b), size)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_extended_set_del_slice(self):
+        indices = (0, None, 1, 3, 19, 300, 1<<333, sys.maxsize,
+            -1, -2, -31, -300)
+        for start in indices:
+            for stop in indices:
+                # Skip invalid step 0
+                for step in indices[1:]:
+                    L = list(range(255))
+                    b = bytearray(L)
+                    # Make sure we have a slice of exactly the right length,
+                    # but with different data.
+                    data = L[start:stop:step]
+                    data.reverse()
+                    L[start:stop:step] = data
+                    b[start:stop:step] = data
+                    self.assertEqual(b, bytearray(L))
+
+                    del L[start:stop:step]
+                    del b[start:stop:step]
+                    self.assertEqual(b, bytearray(L))
+
+    @unittest.skip("TODO: RUSTPYTHON")
+    def test_setslice_trap(self):
+        # This test verifies that we correctly handle assigning self
+        # to a slice of self (the old Lambert Meertens trap).
+        b = bytearray(range(256))
+        b[8:] = b
+        self.assertEqual(b, bytearray(list(range(8)) + list(range(256))))
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_iconcat(self):
+        b = bytearray(b"abc")
+        b1 = b
+        b += b"def"
+        self.assertEqual(b, b"abcdef")
+        self.assertEqual(b, b1)
+        self.assertIs(b, b1)
+        b += b"xyz"
+        self.assertEqual(b, b"abcdefxyz")
+        try:
+            b += ""
+        except TypeError:
+            pass
+        else:
+            self.fail("bytes += unicode didn't raise TypeError")
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_irepeat(self):
+        b = bytearray(b"abc")
+        b1 = b
+        b *= 3
+        self.assertEqual(b, b"abcabcabc")
+        self.assertEqual(b, b1)
+        self.assertIs(b, b1)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_irepeat_1char(self):
+        b = bytearray(b"x")
+        b1 = b
+        b *= 100
+        self.assertEqual(b, b"x"*100)
+        self.assertEqual(b, b1)
+        self.assertIs(b, b1)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_alloc(self):
+        b = bytearray()
+        alloc = b.__alloc__()
+        self.assertGreaterEqual(alloc, 0)
+        seq = [alloc]
+        for i in range(100):
+            b += b"x"
+            alloc = b.__alloc__()
+            self.assertGreater(alloc, len(b))  # including trailing null byte
+            if alloc not in seq:
+                seq.append(alloc)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_init_alloc(self):
+        b = bytearray()
+        def g():
+            for i in range(1, 100):
+                yield i
+                a = list(b)
+                self.assertEqual(a, list(range(1, len(a)+1)))
+                self.assertEqual(len(b), len(a))
+                self.assertLessEqual(len(b), i)
+                alloc = b.__alloc__()
+                self.assertGreater(alloc, len(b))  # including trailing null byte
+        b.__init__(g())
+        self.assertEqual(list(b), list(range(1, 100)))
+        self.assertEqual(len(b), 99)
+        alloc = b.__alloc__()
+        self.assertGreater(alloc, len(b))
+
+    @unittest.skip("TODO: RUSTPYTHON")
+    def test_extend(self):
+        orig = b'hello'
+        a = bytearray(orig)
+        a.extend(a)
+        self.assertEqual(a, orig + orig)
+        self.assertEqual(a[5:], orig)
+        a = bytearray(b'')
+        # Test iterators that don't have a __length_hint__
+        a.extend(map(int, orig * 25))
+        a.extend(int(x) for x in orig * 25)
+        self.assertEqual(a, orig * 50)
+        self.assertEqual(a[-5:], orig)
+        a = bytearray(b'')
+        a.extend(iter(map(int, orig * 50)))
+        self.assertEqual(a, orig * 50)
+        self.assertEqual(a[-5:], orig)
+        a = bytearray(b'')
+        a.extend(list(map(int, orig * 50)))
+        self.assertEqual(a, orig * 50)
+        self.assertEqual(a[-5:], orig)
+        a = bytearray(b'')
+        self.assertRaises(ValueError, a.extend, [0, 1, 2, 256])
+        self.assertRaises(ValueError, a.extend, [0, 1, 2, -1])
+        self.assertEqual(len(a), 0)
+        a = bytearray(b'')
+        a.extend([Indexable(ord('a'))])
+        self.assertEqual(a, b'a')
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_remove(self):
+        b = bytearray(b'hello')
+        b.remove(ord('l'))
+        self.assertEqual(b, b'helo')
+        b.remove(ord('l'))
+        self.assertEqual(b, b'heo')
+        self.assertRaises(ValueError, lambda: b.remove(ord('l')))
+        self.assertRaises(ValueError, lambda: b.remove(400))
+        self.assertRaises(TypeError, lambda: b.remove('e'))
+        # remove first and last
+        b.remove(ord('o'))
+        b.remove(ord('h'))
+        self.assertEqual(b, b'e')
+        self.assertRaises(TypeError, lambda: b.remove(b'e'))
+        b.remove(Indexable(ord('e')))
+        self.assertEqual(b, b'')
+
+        # test values outside of the ascii range: (0, 127)
+        c = bytearray([126, 127, 128, 129])
+        c.remove(127)
+        self.assertEqual(c, bytes([126, 128, 129]))
+        c.remove(129)
+        self.assertEqual(c, bytes([126, 128]))
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_pop(self):
+        b = bytearray(b'world')
+        self.assertEqual(b.pop(), ord('d'))
+        self.assertEqual(b.pop(0), ord('w'))
+        self.assertEqual(b.pop(-2), ord('r'))
+        self.assertRaises(IndexError, lambda: b.pop(10))
+        self.assertRaises(IndexError, lambda: bytearray().pop())
+        # test for issue #6846
+        self.assertEqual(bytearray(b'\xff').pop(), 0xff)
+
+    def test_nosort(self):
+        self.assertRaises(AttributeError, lambda: bytearray().sort())
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_append(self):
+        b = bytearray(b'hell')
+        b.append(ord('o'))
+        self.assertEqual(b, b'hello')
+        self.assertEqual(b.append(100), None)
+        b = bytearray()
+        b.append(ord('A'))
+        self.assertEqual(len(b), 1)
+        self.assertRaises(TypeError, lambda: b.append(b'o'))
+        b = bytearray()
+        b.append(Indexable(ord('A')))
+        self.assertEqual(b, b'A')
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_insert(self):
+        b = bytearray(b'msssspp')
+        b.insert(1, ord('i'))
+        b.insert(4, ord('i'))
+        b.insert(-2, ord('i'))
+        b.insert(1000, ord('i'))
+        self.assertEqual(b, b'mississippi')
+        self.assertRaises(TypeError, lambda: b.insert(0, b'1'))
+        b = bytearray()
+        b.insert(0, Indexable(ord('A')))
+        self.assertEqual(b, b'A')
+
+    def test_copied(self):
+        # Issue 4348.  Make sure that operations that don't mutate the array
+        # copy the bytes.
+        b = bytearray(b'abc')
+        self.assertIsNot(b, b.replace(b'abc', b'cde', 0))
+
+        t = bytearray([i for i in range(256)])
+        x = bytearray(b'')
+        self.assertIsNot(x, x.translate(t))
+
+    @unittest.skip("TODO: RUSTPYTHON")
+    def test_partition_bytearray_doesnt_share_nullstring(self):
+        a, b, c = bytearray(b"x").partition(b"y")
+        self.assertEqual(b, b"")
+        self.assertEqual(c, b"")
+        self.assertIsNot(b, c)
+        b += b"!"
+        self.assertEqual(c, b"")
+        a, b, c = bytearray(b"x").partition(b"y")
+        self.assertEqual(b, b"")
+        self.assertEqual(c, b"")
+        # Same for rpartition
+        b, c, a = bytearray(b"x").rpartition(b"y")
+        self.assertEqual(b, b"")
+        self.assertEqual(c, b"")
+        self.assertIsNot(b, c)
+        b += b"!"
+        self.assertEqual(c, b"")
+        c, b, a = bytearray(b"x").rpartition(b"y")
+        self.assertEqual(b, b"")
+        self.assertEqual(c, b"")
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_resize_forbidden(self):
+        # #4509: can't resize a bytearray when there are buffer exports, even
+        # if it wouldn't reallocate the underlying buffer.
+        # Furthermore, no destructive changes to the buffer may be applied
+        # before raising the error.
+        b = bytearray(range(10))
+        v = memoryview(b)
+        def resize(n):
+            b[1:-1] = range(n + 1, 2*n - 1)
+        resize(10)
+        orig = b[:]
+        self.assertRaises(BufferError, resize, 11)
+        self.assertEqual(b, orig)
+        self.assertRaises(BufferError, resize, 9)
+        self.assertEqual(b, orig)
+        self.assertRaises(BufferError, resize, 0)
+        self.assertEqual(b, orig)
+        # Other operations implying resize
+        self.assertRaises(BufferError, b.pop, 0)
+        self.assertEqual(b, orig)
+        self.assertRaises(BufferError, b.remove, b[1])
+        self.assertEqual(b, orig)
+        def delitem():
+            del b[1]
+        self.assertRaises(BufferError, delitem)
+        self.assertEqual(b, orig)
+        # deleting a non-contiguous slice
+        def delslice():
+            b[1:-1:2] = b""
+        self.assertRaises(BufferError, delslice)
+        self.assertEqual(b, orig)
+
+    @test.support.cpython_only
+    def test_obsolete_write_lock(self):
+        from _testcapi import getbuffer_with_null_view
+        self.assertRaises(BufferError, getbuffer_with_null_view, bytearray())
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_iterator_pickling2(self):
+        orig = bytearray(b'abc')
+        data = list(b'qwerty')
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            # initial iterator
+            itorig = iter(orig)
+            d = pickle.dumps((itorig, orig), proto)
+            it, b = pickle.loads(d)
+            b[:] = data
+            self.assertEqual(type(it), type(itorig))
+            self.assertEqual(list(it), data)
+
+            # running iterator
+            next(itorig)
+            d = pickle.dumps((itorig, orig), proto)
+            it, b = pickle.loads(d)
+            b[:] = data
+            self.assertEqual(type(it), type(itorig))
+            self.assertEqual(list(it), data[1:])
+
+            # empty iterator
+            for i in range(1, len(orig)):
+                next(itorig)
+            d = pickle.dumps((itorig, orig), proto)
+            it, b = pickle.loads(d)
+            b[:] = data
+            self.assertEqual(type(it), type(itorig))
+            self.assertEqual(list(it), data[len(orig):])
+
+            # exhausted iterator
+            self.assertRaises(StopIteration, next, itorig)
+            d = pickle.dumps((itorig, orig), proto)
+            it, b = pickle.loads(d)
+            b[:] = data
+            self.assertEqual(list(it), [])
+
+    test_exhausted_iterator = test.list_tests.CommonTest.test_exhausted_iterator
+
+    def test_iterator_length_hint(self):
+        # Issue 27443: __length_hint__ can return negative integer
+        ba = bytearray(b'ab')
+        it = iter(ba)
+        next(it)
+        ba.clear()
+        # Shouldn't raise an error
+        self.assertEqual(list(it), [])
+
+
+class AssortedBytesTest(unittest.TestCase):
+    #
+    # Test various combinations of bytes and bytearray
+    #
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    @check_bytes_warnings
+    def test_repr_str(self):
+        for f in str, repr:
+            self.assertEqual(f(bytearray()), "bytearray(b'')")
+            self.assertEqual(f(bytearray([0])), "bytearray(b'\\x00')")
+            self.assertEqual(f(bytearray([0, 1, 254, 255])),
+                             "bytearray(b'\\x00\\x01\\xfe\\xff')")
+            self.assertEqual(f(b"abc"), "b'abc'")
+            self.assertEqual(f(b"'"), '''b"'"''') # '''
+            self.assertEqual(f(b"'\""), r"""b'\'"'""") # '
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    @check_bytes_warnings
+    def test_format(self):
+        for b in b'abc', bytearray(b'abc'):
+            self.assertEqual(format(b), str(b))
+            self.assertEqual(format(b, ''), str(b))
+            with self.assertRaisesRegex(TypeError,
+                                        r'\b%s\b' % re.escape(type(b).__name__)):
+                format(b, 's')
+
+    def test_compare_bytes_to_bytearray(self):
+        self.assertEqual(b"abc" == bytes(b"abc"), True)
+        self.assertEqual(b"ab" != bytes(b"abc"), True)
+        self.assertEqual(b"ab" <= bytes(b"abc"), True)
+        self.assertEqual(b"ab" < bytes(b"abc"), True)
+        self.assertEqual(b"abc" >= bytes(b"ab"), True)
+        self.assertEqual(b"abc" > bytes(b"ab"), True)
+
+        self.assertEqual(b"abc" != bytes(b"abc"), False)
+        self.assertEqual(b"ab" == bytes(b"abc"), False)
+        self.assertEqual(b"ab" > bytes(b"abc"), False)
+        self.assertEqual(b"ab" >= bytes(b"abc"), False)
+        self.assertEqual(b"abc" < bytes(b"ab"), False)
+        self.assertEqual(b"abc" <= bytes(b"ab"), False)
+
+        self.assertEqual(bytes(b"abc") == b"abc", True)
+        self.assertEqual(bytes(b"ab") != b"abc", True)
+        self.assertEqual(bytes(b"ab") <= b"abc", True)
+        self.assertEqual(bytes(b"ab") < b"abc", True)
+        self.assertEqual(bytes(b"abc") >= b"ab", True)
+        self.assertEqual(bytes(b"abc") > b"ab", True)
+
+        self.assertEqual(bytes(b"abc") != b"abc", False)
+        self.assertEqual(bytes(b"ab") == b"abc", False)
+        self.assertEqual(bytes(b"ab") > b"abc", False)
+        self.assertEqual(bytes(b"ab") >= b"abc", False)
+        self.assertEqual(bytes(b"abc") < b"ab", False)
+        self.assertEqual(bytes(b"abc") <= b"ab", False)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    @test.support.requires_docstrings
+    def test_doc(self):
+        self.assertIsNotNone(bytearray.__doc__)
+        self.assertTrue(bytearray.__doc__.startswith("bytearray("), bytearray.__doc__)
+        self.assertIsNotNone(bytes.__doc__)
+        self.assertTrue(bytes.__doc__.startswith("bytes("), bytes.__doc__)
+
+    def test_from_bytearray(self):
+        sample = bytes(b"Hello world\n\x80\x81\xfe\xff")
+        buf = memoryview(sample)
+        b = bytearray(buf)
+        self.assertEqual(b, bytearray(sample))
+
+    @check_bytes_warnings
+    def test_to_str(self):
+        self.assertEqual(str(b''), "b''")
+        self.assertEqual(str(b'x'), "b'x'")
+        self.assertEqual(str(b'\x80'), "b'\\x80'")
+        self.assertEqual(str(bytearray(b'')), "bytearray(b'')")
+        self.assertEqual(str(bytearray(b'x')), "bytearray(b'x')")
+        self.assertEqual(str(bytearray(b'\x80')), "bytearray(b'\\x80')")
+
+    def test_literal(self):
+        tests =  [
+            (b"Wonderful spam", "Wonderful spam"),
+            (br"Wonderful spam too", "Wonderful spam too"),
+            (b"\xaa\x00\000\200", "\xaa\x00\000\200"),
+            (br"\xaa\x00\000\200", r"\xaa\x00\000\200"),
+        ]
+        for b, s in tests:
+            self.assertEqual(b, bytearray(s, 'latin-1'))
+        for c in range(128, 256):
+            self.assertRaises(SyntaxError, eval,
+                              'b"%s"' % chr(c))
+
+    def test_split_bytearray(self):
+        self.assertEqual(b'a b'.split(memoryview(b' ')), [b'a', b'b'])
+
+    def test_rsplit_bytearray(self):
+        self.assertEqual(b'a b'.rsplit(memoryview(b' ')), [b'a', b'b'])
+
+    def test_return_self(self):
+        # bytearray.replace must always return a new bytearray
+        b = bytearray()
+        self.assertIsNot(b.replace(b'', b''), b)
+
+    @unittest.skipUnless(sys.flags.bytes_warning,
+                         "BytesWarning is needed for this test: use -bb option")
+    def test_compare(self):
+        def bytes_warning():
+            return test.support.check_warnings(('', BytesWarning))
+        with bytes_warning():
+            b'' == ''
+        with bytes_warning():
+            '' == b''
+        with bytes_warning():
+            b'' != ''
+        with bytes_warning():
+            '' != b''
+        with bytes_warning():
+            bytearray(b'') == ''
+        with bytes_warning():
+            '' == bytearray(b'')
+        with bytes_warning():
+            bytearray(b'') != ''
+        with bytes_warning():
+            '' != bytearray(b'')
+        with bytes_warning():
+            b'\0' == 0
+        with bytes_warning():
+            0 == b'\0'
+        with bytes_warning():
+            b'\0' != 0
+        with bytes_warning():
+            0 != b'\0'
+
+    # Optimizations:
+    # __iter__? (optimization)
+    # __reversed__? (optimization)
+
+    # XXX More string methods?  (Those that don't use character properties)
+
+    # There are tests in string_tests.py that are more
+    # comprehensive for things like partition, etc.
+    # Unfortunately they are all bundled with tests that
+    # are not appropriate for bytes
+
+    # I've started porting some of those into bytearray_tests.py, we should port
+    # the rest that make sense (the code can be cleaned up to use modern
+    # unittest methods at the same time).
+
+class BytearrayPEP3137Test(unittest.TestCase):
+    def marshal(self, x):
+        return bytearray(x)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_returns_new_copy(self):
+        val = self.marshal(b'1234')
+        # On immutable types these MAY return a reference to themselves
+        # but on mutable types like bytearray they MUST return a new copy.
+        for methname in ('zfill', 'rjust', 'ljust', 'center'):
+            method = getattr(val, methname)
+            newval = method(3)
+            self.assertEqual(val, newval)
+            self.assertIsNot(val, newval,
+                            methname+' returned self on a mutable object')
+        for expr in ('val.split()[0]', 'val.rsplit()[0]',
+                     'val.partition(b".")[0]', 'val.rpartition(b".")[2]',
+                     'val.splitlines()[0]', 'val.replace(b"", b"")'):
+            newval = eval(expr)
+            self.assertEqual(val, newval)
+            self.assertIsNot(val, newval,
+                            expr+' returned val on a mutable object')
+        sep = self.marshal(b'')
+        newval = sep.join([val])
+        self.assertEqual(val, newval)
+        self.assertIsNot(val, newval)
+
+
+class FixedStringTest(test.string_tests.BaseTest):
+    def fixtype(self, obj):
+        if isinstance(obj, str):
+            return self.type2test(obj.encode("utf-8"))
+        return super().fixtype(obj)
+
+    contains_bytes = True
+
+class ByteArrayAsStringTest(FixedStringTest, unittest.TestCase):
+    type2test = bytearray
+
+class BytesAsStringTest(FixedStringTest, unittest.TestCase):
+    type2test = bytes
+
+
+class SubclassTest:
+
+    def test_basic(self):
+        self.assertTrue(issubclass(self.type2test, self.basetype))
+        self.assertIsInstance(self.type2test(), self.basetype)
+
+        a, b = b"abcd", b"efgh"
+        _a, _b = self.type2test(a), self.type2test(b)
+
+        # test comparison operators with subclass instances
+        self.assertTrue(_a == _a)
+        self.assertTrue(_a != _b)
+        self.assertTrue(_a < _b)
+        self.assertTrue(_a <= _b)
+        self.assertTrue(_b >= _a)
+        self.assertTrue(_b > _a)
+        self.assertIsNot(_a, a)
+
+        # test concat of subclass instances
+        self.assertEqual(a + b, _a + _b)
+        self.assertEqual(a + b, a + _b)
+        self.assertEqual(a + b, _a + b)
+
+        # test repeat
+        self.assertTrue(a*5 == _a*5)
+
+    def test_join(self):
+        # Make sure join returns a NEW object for single item sequences
+        # involving a subclass.
+        # Make sure that it is of the appropriate type.
+        s1 = self.type2test(b"abcd")
+        s2 = self.basetype().join([s1])
+        self.assertIsNot(s1, s2)
+        self.assertIs(type(s2), self.basetype, type(s2))
+
+        # Test reverse, calling join on subclass
+        s3 = s1.join([b"abcd"])
+        self.assertIs(type(s3), self.basetype)
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_pickle(self):
+        a = self.type2test(b"abcd")
+        a.x = 10
+        a.y = self.type2test(b"efgh")
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            b = pickle.loads(pickle.dumps(a, proto))
+            self.assertNotEqual(id(a), id(b))
+            self.assertEqual(a, b)
+            self.assertEqual(a.x, b.x)
+            self.assertEqual(a.y, b.y)
+            self.assertEqual(type(a), type(b))
+            self.assertEqual(type(a.y), type(b.y))
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_copy(self):
+        a = self.type2test(b"abcd")
+        a.x = 10
+        a.y = self.type2test(b"efgh")
+        for copy_method in (copy.copy, copy.deepcopy):
+            b = copy_method(a)
+            self.assertNotEqual(id(a), id(b))
+            self.assertEqual(a, b)
+            self.assertEqual(a.x, b.x)
+            self.assertEqual(a.y, b.y)
+            self.assertEqual(type(a), type(b))
+            self.assertEqual(type(a.y), type(b.y))
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_fromhex(self):
+        b = self.type2test.fromhex('1a2B30')
+        self.assertEqual(b, b'\x1a\x2b\x30')
+        self.assertIs(type(b), self.type2test)
+
+        class B1(self.basetype):
+            def __new__(cls, value):
+                me = self.basetype.__new__(cls, value)
+                me.foo = 'bar'
+                return me
+
+        b = B1.fromhex('1a2B30')
+        self.assertEqual(b, b'\x1a\x2b\x30')
+        self.assertIs(type(b), B1)
+        self.assertEqual(b.foo, 'bar')
+
+        class B2(self.basetype):
+            def __init__(me, *args, **kwargs):
+                if self.basetype is not bytes:
+                    self.basetype.__init__(me, *args, **kwargs)
+                me.foo = 'bar'
+
+        b = B2.fromhex('1a2B30')
+        self.assertEqual(b, b'\x1a\x2b\x30')
+        self.assertIs(type(b), B2)
+        self.assertEqual(b.foo, 'bar')
+
+
+class ByteArraySubclass(bytearray):
+    pass
+
+class BytesSubclass(bytes):
+    pass
+
+class OtherBytesSubclass(bytes):
+    pass
+
+class ByteArraySubclassTest(SubclassTest, unittest.TestCase):
+    basetype = bytearray
+    type2test = ByteArraySubclass
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_init_override(self):
+        class subclass(bytearray):
+            def __init__(me, newarg=1, *args, **kwargs):
+                bytearray.__init__(me, *args, **kwargs)
+        x = subclass(4, b"abcd")
+        x = subclass(4, source=b"abcd")
+        self.assertEqual(x, b"abcd")
+        x = subclass(newarg=4, source=b"abcd")
+        self.assertEqual(x, b"abcd")
+
+
+class BytesSubclassTest(SubclassTest, unittest.TestCase):
+    basetype = bytes
+    type2test = BytesSubclass
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/vm/src/obj/objbyteinner.rs b/vm/src/obj/objbyteinner.rs
index a507900e8..a6be44013 100644
--- a/vm/src/obj/objbyteinner.rs
+++ b/vm/src/obj/objbyteinner.rs
@@ -248,11 +248,11 @@ pub struct ByteInnerSplitOptions {
     #[pyarg(positional_or_keyword, optional = true)]
     sep: OptionalArg<Option<PyByteInner>>,
     #[pyarg(positional_or_keyword, optional = true)]
-    maxsplit: OptionalArg<i32>,
+    maxsplit: OptionalArg<isize>,
 }
 
 impl ByteInnerSplitOptions {
-    pub fn get_value(self) -> PyResult<(Vec<u8>, i32)> {
+    pub fn get_value(self) -> PyResult<(Vec<u8>, isize)> {
         let sep = match self.sep.into_option() {
             Some(Some(bytes)) => bytes.elements,
             _ => vec![],
@@ -374,6 +374,9 @@ impl PyByteInner {
     ) -> PyResult<bool> {
         match needle {
             Either::A(byte) => {
+                if byte.elements.is_empty() {
+                    return Ok(true);
+                }
                 let other = &byte.elements[..];
                 for (n, i) in self.elements.iter().enumerate() {
                     if n + other.len() <= self.len()
@@ -1228,7 +1231,7 @@ pub enum ByteInnerPosition {
     All,
 }
 
-fn split_slice<'a>(slice: &'a [u8], sep: &[u8], maxsplit: i32) -> Vec<&'a [u8]> {
+fn split_slice<'a>(slice: &'a [u8], sep: &[u8], maxsplit: isize) -> Vec<&'a [u8]> {
     let mut splitted: Vec<&[u8]> = vec![];
     let mut prev_index = 0;
     let mut index = 0;
@@ -1319,7 +1322,7 @@ fn split_slice<'a>(slice: &'a [u8], sep: &[u8], maxsplit: i32) -> Vec<&'a [u8]>
     splitted
 }
 
-fn split_slice_reverse<'a>(slice: &'a [u8], sep: &[u8], maxsplit: i32) -> Vec<&'a [u8]> {
+fn split_slice_reverse<'a>(slice: &'a [u8], sep: &[u8], maxsplit: isize) -> Vec<&'a [u8]> {
     let mut splitted: Vec<&[u8]> = vec![];
     let mut prev_index = slice.len();
     let mut index = slice.len();