diff --git a/Lib/test/test_opcache.py b/Lib/test/test_opcache.py
index fad3cd2db..aeb4de6ca 100644
--- a/Lib/test/test_opcache.py
+++ b/Lib/test/test_opcache.py
@@ -1,4 +1,61 @@
+import copy
+import pickle
+import dis
+import threading
+import types
 import unittest
+from test.support import threading_helper, check_impl_detail, requires_specialization
+from test.support.import_helper import import_module
+
+# Skip this module on other interpreters, it is cpython specific:
+if check_impl_detail(cpython=False):
+    raise unittest.SkipTest('implementation detail specific to cpython')
+
+_testinternalcapi = import_module("_testinternalcapi")
+
+
+def disabling_optimizer(func):
+    def wrapper(*args, **kwargs):
+        if not hasattr(_testinternalcapi, "get_optimizer"):
+            return func(*args, **kwargs)
+        old_opt = _testinternalcapi.get_optimizer()
+        _testinternalcapi.set_optimizer(None)
+        try:
+            return func(*args, **kwargs)
+        finally:
+            _testinternalcapi.set_optimizer(old_opt)
+
+    return wrapper
+
+
+class TestBase(unittest.TestCase):
+    def assert_specialized(self, f, opname):
+        instructions = dis.get_instructions(f, adaptive=True)
+        opnames = {instruction.opname for instruction in instructions}
+        self.assertIn(opname, opnames)
+
+
+class TestLoadSuperAttrCache(unittest.TestCase):
+    def test_descriptor_not_double_executed_on_spec_fail(self):
+        calls = []
+        class Descriptor:
+            def __get__(self, instance, owner):
+                calls.append((instance, owner))
+                return lambda: 1
+
+        class C:
+            d = Descriptor()
+
+        class D(C):
+            def f(self):
+                return super().d()
+
+        d = D()
+
+        self.assertEqual(d.f(), 1)  # warmup
+        calls.clear()
+        self.assertEqual(d.f(), 1)  # try to specialize
+        self.assertEqual(calls, [(d, D)])
 
 
 class TestLoadAttrCache(unittest.TestCase):
@@ -177,8 +234,6 @@ class TestLoadAttrCache(unittest.TestCase):
         for _ in range(1025):
             self.assertFalse(f())
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_load_shadowing_slot_should_raise_type_error(self):
         class Class:
             __slots__ = ("slot",)
@@ -214,7 +269,6 @@ class TestLoadAttrCache(unittest.TestCase):
             with self.assertRaises(TypeError):
                 f(o)
 
-    @unittest.skip("TODO: RUSTPYTHON")
     def test_load_borrowed_slot_should_not_crash(self):
         class Class:
             __slots__ = ("slot",)
@@ -231,7 +285,6 @@ class TestLoadAttrCache(unittest.TestCase):
             with self.assertRaises(TypeError):
                 f(o)
 
-    @unittest.skip("TODO: RUSTPYTHON")
     def test_store_borrowed_slot_should_not_crash(self):
         class Class:
             __slots__ = ("slot",)
@@ -433,6 +486,693 @@ class TestLoadMethodCache(unittest.TestCase):
             self.assertFalse(f())
 
 
+class TestCallCache(TestBase):
+    def test_too_many_defaults_0(self):
+        def f():
+            pass
+
+        f.__defaults__ = (None,)
+        for _ in range(1025):
+            f()
+
+    def test_too_many_defaults_1(self):
+        def f(x):
+            pass
+
+        f.__defaults__ = (None, None)
+        for _ in range(1025):
+            f(None)
+            f()
+
+    def test_too_many_defaults_2(self):
+        def f(x, y):
+            pass
+
+        f.__defaults__ = (None, None, None)
+        for _ in range(1025):
+            f(None, None)
+            f(None)
+            f()
+
+    @disabling_optimizer
+    @requires_specialization
+    def test_assign_init_code(self):
+        class MyClass:
+            def __init__(self):
+                pass
+
+        def instantiate():
+            return MyClass()
+
+        # Trigger specialization
+        for _ in range(1025):
+            instantiate()
+        self.assert_specialized(instantiate, "CALL_ALLOC_AND_ENTER_INIT")
+
+        def count_args(self, *args):
+            self.num_args = len(args)
+
+        # Set MyClass.__init__.__code__ to a code object that is incompatible
+        # (uses varargs) with the current specialization
+        MyClass.__init__.__code__ = count_args.__code__
+        instantiate()
+
+
+@threading_helper.requires_working_threading()
+@requires_specialization
+class TestRacesDoNotCrash(TestBase):
+    # Careful with these. Bigger numbers have a higher chance of catching bugs,
+    # but you can also burn through a *ton* of type/dict/function versions:
+    ITEMS = 1000
+    LOOPS = 4
+    WARMUPS = 2
+    WRITERS = 2
+
+    @disabling_optimizer
+    def assert_races_do_not_crash(
+        self, opname, get_items, read, write, *, check_items=False
+    ):
+        # This might need a few dozen loops in some cases:
+        for _ in range(self.LOOPS):
+            items = get_items()
+            # Reset:
+            if check_items:
+                for item in items:
+                    item.__code__ = item.__code__.replace()
+            else:
+                read.__code__ = read.__code__.replace()
+            # Specialize:
+            for _ in range(self.WARMUPS):
+                read(items)
+            if check_items:
+                for item in items:
+                    self.assert_specialized(item, opname)
+            else:
+                self.assert_specialized(read, opname)
+            # Create writers:
+            writers = []
+            for _ in range(self.WRITERS):
+                writer = threading.Thread(target=write, args=[items])
+                writers.append(writer)
+            # Run:
+            for writer in writers:
+                writer.start()
+            read(items)  # BOOM!
+            for writer in writers:
+                writer.join()
+
+    def test_binary_subscr_getitem(self):
+        def get_items():
+            class C:
+                __getitem__ = lambda self, item: None
+
+            items = []
+            for _ in range(self.ITEMS):
+                item = C()
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                try:
+                    item[None]
+                except TypeError:
+                    pass
+
+        def write(items):
+            for item in items:
+                try:
+                    del item.__getitem__
+                except AttributeError:
+                    pass
+                type(item).__getitem__ = lambda self, item: None
+
+        opname = "BINARY_SUBSCR_GETITEM"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+    def test_binary_subscr_list_int(self):
+        def get_items():
+            items = []
+            for _ in range(self.ITEMS):
+                item = [None]
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                try:
+                    item[0]
+                except IndexError:
+                    pass
+
+        def write(items):
+            for item in items:
+                item.clear()
+                item.append(None)
+
+        opname = "BINARY_SUBSCR_LIST_INT"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+    def test_for_iter_gen(self):
+        def get_items():
+            def g():
+                yield
+                yield
+
+            items = []
+            for _ in range(self.ITEMS):
+                item = g()
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                try:
+                    for _ in item:
+                        break
+                except ValueError:
+                    pass
+
+        def write(items):
+            for item in items:
+                try:
+                    for _ in item:
+                        break
+                except ValueError:
+                    pass
+
+        opname = "FOR_ITER_GEN"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+    def test_for_iter_list(self):
+        def get_items():
+            items = []
+            for _ in range(self.ITEMS):
+                item = [None]
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                for item in item:
+                    break
+
+        def write(items):
+            for item in items:
+                item.clear()
+                item.append(None)
+
+        opname = "FOR_ITER_LIST"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+    def test_load_attr_class(self):
+        def get_items():
+            class C:
+                a = object()
+
+            items = []
+            for _ in range(self.ITEMS):
+                item = C
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                try:
+                    item.a
+                except AttributeError:
+                    pass
+
+        def write(items):
+            for item in items:
+                try:
+                    del item.a
+                except AttributeError:
+                    pass
+                item.a = object()
+
+        opname = "LOAD_ATTR_CLASS"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+    def test_load_attr_getattribute_overridden(self):
+        def get_items():
+            class C:
+                __getattribute__ = lambda self, name: None
+
+            items = []
+            for _ in range(self.ITEMS):
+                item = C()
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                try:
+                    item.a
+                except AttributeError:
+                    pass
+
+        def write(items):
+            for item in items:
+                try:
+                    del item.__getattribute__
+                except AttributeError:
+                    pass
+                type(item).__getattribute__ = lambda self, name: None
+
+        opname = "LOAD_ATTR_GETATTRIBUTE_OVERRIDDEN"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+    def test_load_attr_instance_value(self):
+        def get_items():
+            class C:
+                pass
+
+            items = []
+            for _ in range(self.ITEMS):
+                item = C()
+                item.a = None
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                item.a
+
+        def write(items):
+            for item in items:
+                item.__dict__[None] = None
+
+        opname = "LOAD_ATTR_INSTANCE_VALUE"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+    def test_load_attr_method_lazy_dict(self):
+        def get_items():
+            class C(Exception):
+                m = lambda self: None
+
+            items = []
+            for _ in range(self.ITEMS):
+                item = C()
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                try:
+                    item.m()
+                except AttributeError:
+                    pass
+
+        def write(items):
+            for item in items:
+                try:
+                    del item.m
+                except AttributeError:
+                    pass
+                type(item).m = lambda self: None
+
+        opname = "LOAD_ATTR_METHOD_LAZY_DICT"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+    def test_load_attr_method_no_dict(self):
+        def get_items():
+            class C:
+                __slots__ = ()
+                m = lambda self: None
+
+            items = []
+            for _ in range(self.ITEMS):
+                item = C()
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                try:
+                    item.m()
+                except AttributeError:
+                    pass
+
+        def write(items):
+            for item in items:
+                try:
+                    del item.m
+                except AttributeError:
+                    pass
+                type(item).m = lambda self: None
+
+        opname = "LOAD_ATTR_METHOD_NO_DICT"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+    def test_load_attr_method_with_values(self):
+        def get_items():
+            class C:
+                m = lambda self: None
+
+            items = []
+            for _ in range(self.ITEMS):
+                item = C()
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                try:
+                    item.m()
+                except AttributeError:
+                    pass
+
+        def write(items):
+            for item in items:
+                try:
+                    del item.m
+                except AttributeError:
+                    pass
+                type(item).m = lambda self: None
+
+        opname = "LOAD_ATTR_METHOD_WITH_VALUES"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+    def test_load_attr_module(self):
+        def get_items():
+            items = []
+            for _ in range(self.ITEMS):
+                item = types.ModuleType("<item>")
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                try:
+                    item.__name__
+                except AttributeError:
+                    pass
+
+        def write(items):
+            for item in items:
+                d = item.__dict__.copy()
+                item.__dict__.clear()
+                item.__dict__.update(d)
+
+        opname = "LOAD_ATTR_MODULE"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+    def test_load_attr_property(self):
+        def get_items():
+            class C:
+                a = property(lambda self: None)
+
+            items = []
+            for _ in range(self.ITEMS):
+                item = C()
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                try:
+                    item.a
+                except AttributeError:
+                    pass
+
+        def write(items):
+            for item in items:
+                try:
+                    del type(item).a
+                except AttributeError:
+                    pass
+                type(item).a = property(lambda self: None)
+
+        opname = "LOAD_ATTR_PROPERTY"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+    def test_load_attr_with_hint(self):
+        def get_items():
+            class C:
+                pass
+
+            items = []
+            for _ in range(self.ITEMS):
+                item = C()
+                item.a = None
+                # Resize into a combined unicode dict:
+                for i in range(29):
+                    setattr(item, f"_{i}", None)
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                item.a
+
+        def write(items):
+            for item in items:
+                item.__dict__[None] = None
+
+        opname = "LOAD_ATTR_WITH_HINT"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+    def test_load_global_module(self):
+        def get_items():
+            items = []
+            for _ in range(self.ITEMS):
+                item = eval("lambda: x", {"x": None})
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                item()
+
+        def write(items):
+            for item in items:
+                item.__globals__[None] = None
+
+        opname = "LOAD_GLOBAL_MODULE"
+        self.assert_races_do_not_crash(
+            opname, get_items, read, write, check_items=True
+        )
+
+    def test_store_attr_instance_value(self):
+        def get_items():
+            class C:
+                pass
+
+            items = []
+            for _ in range(self.ITEMS):
+                item = C()
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                item.a = None
+
+        def write(items):
+            for item in items:
+                item.__dict__[None] = None
+
+        opname = "STORE_ATTR_INSTANCE_VALUE"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+    def test_store_attr_with_hint(self):
+        def get_items():
+            class C:
+                pass
+
+            items = []
+            for _ in range(self.ITEMS):
+                item = C()
+                # Resize into a combined unicode dict:
+                for i in range(29):
+                    setattr(item, f"_{i}", None)
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                item.a = None
+
+        def write(items):
+            for item in items:
+                item.__dict__[None] = None
+
+        opname = "STORE_ATTR_WITH_HINT"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+    def test_store_subscr_list_int(self):
+        def get_items():
+            items = []
+            for _ in range(self.ITEMS):
+                item = [None]
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                try:
+                    item[0] = None
+                except IndexError:
+                    pass
+
+        def write(items):
+            for item in items:
+                item.clear()
+                item.append(None)
+
+        opname = "STORE_SUBSCR_LIST_INT"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+    def test_unpack_sequence_list(self):
+        def get_items():
+            items = []
+            for _ in range(self.ITEMS):
+                item = [None]
+                items.append(item)
+            return items
+
+        def read(items):
+            for item in items:
+                try:
+                    [_] = item
+                except ValueError:
+                    pass
+
+        def write(items):
+            for item in items:
+                item.clear()
+                item.append(None)
+
+        opname = "UNPACK_SEQUENCE_LIST"
+        self.assert_races_do_not_crash(opname, get_items, read, write)
+
+class C:
+    pass
+
+@requires_specialization
+class TestInstanceDict(unittest.TestCase):
+
+    def setUp(self):
+        c = C()
+        c.a, c.b, c.c = 0,0,0
+
+    def test_values_on_instance(self):
+        c = C()
+        c.a = 1
+        C().b = 2
+        c.c = 3
+        self.assertEqual(
+            _testinternalcapi.get_object_dict_values(c),
+            (1, '<NULL>', 3)
+        )
+
+    def test_dict_materialization(self):
+        c = C()
+        c.a = 1
+        c.b = 2
+        c.__dict__
+        self.assertEqual(c.__dict__, {"a":1, "b": 2})
+
+    def test_dict_dematerialization(self):
+        c = C()
+        c.a = 1
+        c.b = 2
+        c.__dict__
+        for _ in range(100):
+            c.a
+        self.assertEqual(
+            _testinternalcapi.get_object_dict_values(c),
+            (1, 2, '<NULL>')
+        )
+
+    def test_dict_dematerialization_multiple_refs(self):
+        c = C()
+        c.a = 1
+        c.b = 2
+        d = c.__dict__
+        for _ in range(100):
+            c.a
+        self.assertIs(c.__dict__, d)
+
+    def test_dict_dematerialization_copy(self):
+        c = C()
+        c.a = 1
+        c.b = 2
+        c2 = copy.copy(c)
+        for _ in range(100):
+            c.a
+            c2.a
+        self.assertEqual(
+            _testinternalcapi.get_object_dict_values(c),
+            (1, 2, '<NULL>')
+        )
+        self.assertEqual(
+            _testinternalcapi.get_object_dict_values(c2),
+            (1, 2, '<NULL>')
+        )
+        c3 = copy.deepcopy(c)
+        for _ in range(100):
+            c.a
+            c3.a
+        self.assertEqual(
+            _testinternalcapi.get_object_dict_values(c),
+            (1, 2, '<NULL>')
+        )
+        #NOTE -- c3.__dict__ does not de-materialize
+
+    def test_dict_dematerialization_pickle(self):
+        c = C()
+        c.a = 1
+        c.b = 2
+        c2 = pickle.loads(pickle.dumps(c))
+        for _ in range(100):
+            c.a
+            c2.a
+        self.assertEqual(
+            _testinternalcapi.get_object_dict_values(c),
+            (1, 2, '<NULL>')
+        )
+        self.assertEqual(
+            _testinternalcapi.get_object_dict_values(c2),
+            (1, 2, '<NULL>')
+        )
+
+    def test_dict_dematerialization_subclass(self):
+        class D(dict): pass
+        c = C()
+        c.a = 1
+        c.b = 2
+        c.__dict__ = D(c.__dict__)
+        for _ in range(100):
+            c.a
+        self.assertIs(
+            _testinternalcapi.get_object_dict_values(c),
+            None
+        )
+        self.assertEqual(
+            c.__dict__,
+            {'a':1, 'b':2}
+        )
+
+    def test_store_attr_with_hint(self):
+        # gh-133441: Regression test for STORE_ATTR_WITH_HINT bytecode
+        class Node:
+            def __init__(self):
+                self.parents = {}
+
+            def __setstate__(self, data_dict):
+                self.__dict__ = data_dict
+                self.parents = {}
+
+        class Dict(dict):
+            pass
+
+        obj = Node()
+        obj.__setstate__({'parents': {}})
+        obj.__setstate__({'parents': {}})
+        obj.__setstate__(Dict({'parents': {}}))
+
+
 if __name__ == "__main__":
-    import unittest
     unittest.main()