diff --git a/test/__init__.py b/test/__init__.py
index d3a63db2d5..b49eee99ac 100644
--- a/test/__init__.py
+++ b/test/__init__.py
@@ -17,6 +17,7 @@
 
 import asyncio
 import gc
+import inspect
 import logging
 import multiprocessing
 import os
@@ -30,28 +31,6 @@
 import unittest
 import warnings
 from asyncio import iscoroutinefunction
-from test.helpers import (
-    COMPRESSORS,
-    IS_SRV,
-    MONGODB_API_VERSION,
-    MULTI_MONGOS_LB_URI,
-    TEST_LOADBALANCER,
-    TEST_SERVERLESS,
-    TLS_OPTIONS,
-    SystemCertsPatcher,
-    client_knobs,
-    db_pwd,
-    db_user,
-    global_knobs,
-    host,
-    is_server_resolvable,
-    port,
-    print_running_topology,
-    print_thread_stacks,
-    print_thread_tracebacks,
-    sanitize_cmd,
-    sanitize_reply,
-)
 
 from pymongo.uri_parser import parse_uri
 
@@ -63,7 +42,6 @@
     HAVE_IPADDRESS = False
 from contextlib import contextmanager
 from functools import partial, wraps
-from test.version import Version
 from typing import Any, Callable, Dict, Generator, overload
 from unittest import SkipTest
 from urllib.parse import quote_plus
@@ -78,6 +56,32 @@
 from pymongo.synchronous.database import Database
 from pymongo.synchronous.mongo_client import MongoClient
 
+sys.path[0:0] = [""]
+
+from test.helpers import (
+    COMPRESSORS,
+    IS_SRV,
+    MONGODB_API_VERSION,
+    MULTI_MONGOS_LB_URI,
+    TEST_LOADBALANCER,
+    TEST_SERVERLESS,
+    TLS_OPTIONS,
+    SystemCertsPatcher,
+    client_knobs,
+    db_pwd,
+    db_user,
+    global_knobs,
+    host,
+    is_server_resolvable,
+    port,
+    print_running_topology,
+    print_thread_stacks,
+    print_thread_tracebacks,
+    sanitize_cmd,
+    sanitize_reply,
+)
+from test.version import Version
+
 _IS_SYNC = True
 
 
@@ -863,18 +867,66 @@ def max_message_size_bytes(self):
 # Reusable client context
 client_context = ClientContext()
 
+# Global event loop for async tests.
+LOOP = None
 
-def reset_client_context():
-    if _IS_SYNC:
-        # sync tests don't need to reset a client context
-        return
-    elif client_context.client is not None:
-        client_context.client.close()
-        client_context.client = None
-    client_context._init_client()
+
+def get_loop() -> asyncio.AbstractEventLoop:
+    """Get the test suite's global event loop."""
+    global LOOP
+    if LOOP is None:
+        try:
+            LOOP = asyncio.get_running_loop()
+        except RuntimeError:
+            # no running event loop, fallback to get_event_loop.
+            try:
+                # Ignore DeprecationWarning: There is no current event loop
+                with warnings.catch_warnings():
+                    warnings.simplefilter("ignore", DeprecationWarning)
+                    LOOP = asyncio.get_event_loop()
+            except RuntimeError:
+                LOOP = asyncio.new_event_loop()
+                asyncio.set_event_loop(LOOP)
+    return LOOP
 
 
 class PyMongoTestCase(unittest.TestCase):
+    if not _IS_SYNC:
+        # An async TestCase that uses a single event loop for all tests.
+        # Inspired by TestCase.
+        def setUp(self):
+            pass
+
+        def tearDown(self):
+            pass
+
+        def addCleanup(self, func, /, *args, **kwargs):
+            self.addCleanup(*(func, *args), **kwargs)
+
+        def _callSetUp(self):
+            self.setUp()
+            self._callAsync(self.setUp)
+
+        def _callTestMethod(self, method):
+            self._callMaybeAsync(method)
+
+        def _callTearDown(self):
+            self._callAsync(self.tearDown)
+            self.tearDown()
+
+        def _callCleanup(self, function, *args, **kwargs):
+            self._callMaybeAsync(function, *args, **kwargs)
+
+        def _callAsync(self, func, /, *args, **kwargs):
+            assert inspect.iscoroutinefunction(func), f"{func!r} is not an async function"
+            return get_loop().run_until_complete(func(*args, **kwargs))
+
+        def _callMaybeAsync(self, func, /, *args, **kwargs):
+            if inspect.iscoroutinefunction(func):
+                return get_loop().run_until_complete(func(*args, **kwargs))
+            else:
+                return func(*args, **kwargs)
+
     def assertEqualCommand(self, expected, actual, msg=None):
         self.assertEqual(sanitize_cmd(expected), sanitize_cmd(actual), msg)
 
@@ -1136,8 +1188,6 @@ class IntegrationTest(PyMongoTestCase):
 
     @client_context.require_connection
     def setUp(self) -> None:
-        if not _IS_SYNC:
-            reset_client_context()
         if client_context.load_balancer and not getattr(self, "RUN_ON_LOAD_BALANCER", False):
             raise SkipTest("this test does not support load balancers")
         if client_context.serverless and not getattr(self, "RUN_ON_SERVERLESS", False):
@@ -1186,6 +1236,9 @@ def tearDown(self) -> None:
 
 
 def setup():
+    if not _IS_SYNC:
+        # Set up the event loop.
+        get_loop()
     client_context.init()
     warnings.resetwarnings()
     warnings.simplefilter("always")
diff --git a/test/asynchronous/__init__.py b/test/asynchronous/__init__.py
index 73e2824742..76fae407da 100644
--- a/test/asynchronous/__init__.py
+++ b/test/asynchronous/__init__.py
@@ -17,6 +17,7 @@
 
 import asyncio
 import gc
+import inspect
 import logging
 import multiprocessing
 import os
@@ -30,28 +31,6 @@
 import unittest
 import warnings
 from asyncio import iscoroutinefunction
-from test.helpers import (
-    COMPRESSORS,
-    IS_SRV,
-    MONGODB_API_VERSION,
-    MULTI_MONGOS_LB_URI,
-    TEST_LOADBALANCER,
-    TEST_SERVERLESS,
-    TLS_OPTIONS,
-    SystemCertsPatcher,
-    client_knobs,
-    db_pwd,
-    db_user,
-    global_knobs,
-    host,
-    is_server_resolvable,
-    port,
-    print_running_topology,
-    print_thread_stacks,
-    print_thread_tracebacks,
-    sanitize_cmd,
-    sanitize_reply,
-)
 
 from pymongo.uri_parser import parse_uri
 
@@ -63,7 +42,6 @@
     HAVE_IPADDRESS = False
 from contextlib import asynccontextmanager, contextmanager
 from functools import partial, wraps
-from test.version import Version
 from typing import Any, Callable, Dict, Generator, overload
 from unittest import SkipTest
 from urllib.parse import quote_plus
@@ -78,6 +56,32 @@
 from pymongo.server_api import ServerApi
 from pymongo.ssl_support import HAVE_SSL, _ssl  # type:ignore[attr-defined]
 
+sys.path[0:0] = [""]
+
+from test.helpers import (
+    COMPRESSORS,
+    IS_SRV,
+    MONGODB_API_VERSION,
+    MULTI_MONGOS_LB_URI,
+    TEST_LOADBALANCER,
+    TEST_SERVERLESS,
+    TLS_OPTIONS,
+    SystemCertsPatcher,
+    client_knobs,
+    db_pwd,
+    db_user,
+    global_knobs,
+    host,
+    is_server_resolvable,
+    port,
+    print_running_topology,
+    print_thread_stacks,
+    print_thread_tracebacks,
+    sanitize_cmd,
+    sanitize_reply,
+)
+from test.version import Version
+
 _IS_SYNC = False
 
 
@@ -865,18 +869,66 @@ async def max_message_size_bytes(self):
 # Reusable client context
 async_client_context = AsyncClientContext()
 
+# Global event loop for async tests.
+LOOP = None
+
+
+def get_loop() -> asyncio.AbstractEventLoop:
+    """Get the test suite's global event loop."""
+    global LOOP
+    if LOOP is None:
+        try:
+            LOOP = asyncio.get_running_loop()
+        except RuntimeError:
+            # no running event loop, fallback to get_event_loop.
+            try:
+                # Ignore DeprecationWarning: There is no current event loop
+                with warnings.catch_warnings():
+                    warnings.simplefilter("ignore", DeprecationWarning)
+                    LOOP = asyncio.get_event_loop()
+            except RuntimeError:
+                LOOP = asyncio.new_event_loop()
+                asyncio.set_event_loop(LOOP)
+    return LOOP
+
+
+class AsyncPyMongoTestCase(unittest.TestCase):
+    if not _IS_SYNC:
+        # An async TestCase that uses a single event loop for all tests.
+        # Inspired by IsolatedAsyncioTestCase.
+        async def asyncSetUp(self):
+            pass
 
-async def reset_client_context():
-    if _IS_SYNC:
-        # sync tests don't need to reset a client context
-        return
-    elif async_client_context.client is not None:
-        await async_client_context.client.close()
-        async_client_context.client = None
-    await async_client_context._init_client()
+        async def asyncTearDown(self):
+            pass
 
+        def addAsyncCleanup(self, func, /, *args, **kwargs):
+            self.addCleanup(*(func, *args), **kwargs)
+
+        def _callSetUp(self):
+            self.setUp()
+            self._callAsync(self.asyncSetUp)
+
+        def _callTestMethod(self, method):
+            self._callMaybeAsync(method)
+
+        def _callTearDown(self):
+            self._callAsync(self.asyncTearDown)
+            self.tearDown()
+
+        def _callCleanup(self, function, *args, **kwargs):
+            self._callMaybeAsync(function, *args, **kwargs)
+
+        def _callAsync(self, func, /, *args, **kwargs):
+            assert inspect.iscoroutinefunction(func), f"{func!r} is not an async function"
+            return get_loop().run_until_complete(func(*args, **kwargs))
+
+        def _callMaybeAsync(self, func, /, *args, **kwargs):
+            if inspect.iscoroutinefunction(func):
+                return get_loop().run_until_complete(func(*args, **kwargs))
+            else:
+                return func(*args, **kwargs)
 
-class AsyncPyMongoTestCase(unittest.IsolatedAsyncioTestCase):
     def assertEqualCommand(self, expected, actual, msg=None):
         self.assertEqual(sanitize_cmd(expected), sanitize_cmd(actual), msg)
 
@@ -1154,8 +1206,6 @@ class AsyncIntegrationTest(AsyncPyMongoTestCase):
 
     @async_client_context.require_connection
     async def asyncSetUp(self) -> None:
-        if not _IS_SYNC:
-            await reset_client_context()
         if async_client_context.load_balancer and not getattr(self, "RUN_ON_LOAD_BALANCER", False):
             raise SkipTest("this test does not support load balancers")
         if async_client_context.serverless and not getattr(self, "RUN_ON_SERVERLESS", False):
@@ -1204,6 +1254,9 @@ async def asyncTearDown(self) -> None:
 
 
 async def async_setup():
+    if not _IS_SYNC:
+        # Set up the event loop.
+        get_loop()
     await async_client_context.init()
     warnings.resetwarnings()
     warnings.simplefilter("always")