@@ -5,58 +5,87 @@
 
 from contextvars import ContextVar
 from unittest import mock
+from test.test_asyncio import utils as test_utils
 
 
 def tearDownModule():
     asyncio.set_event_loop_policy(None)
 
 
-class ToThreadTests(unittest.IsolatedAsyncioTestCase):
-    async def test_to_thread(self):
-        result = await asyncio.to_thread(sum, [40, 2])
+class ToThreadTests(test_utils.TestCase):
+    def setUp(self):
+        super().setUp()
+        self.loop = asyncio.new_event_loop()
+        asyncio.set_event_loop(self.loop)
+
+    def tearDown(self):
+        self.loop.run_until_complete(
+            self.loop.shutdown_default_executor())
+        self.loop.close()
+        asyncio.set_event_loop(None)
+        self.loop = None
+        super().tearDown()
+
+    def test_to_thread(self):
+        async def main():
+            return await asyncio.to_thread(sum, [40, 2])
+
+        result = self.loop.run_until_complete(main())
         self.assertEqual(result, 42)
 
-    async def test_to_thread_exception(self):
+    def test_to_thread_exception(self):
         def raise_runtime():
             raise RuntimeError("test")
 
-        with self.assertRaisesRegex(RuntimeError, "test"):
+        async def main():
             await asyncio.to_thread(raise_runtime)
 
-    async def test_to_thread_once(self):
+        with self.assertRaisesRegex(RuntimeError, "test"):
+            self.loop.run_until_complete(main())
+
+    def test_to_thread_once(self):
         func = mock.Mock()
 
-        await asyncio.to_thread(func)
+        async def main():
+            await asyncio.to_thread(func)
+
+        self.loop.run_until_complete(main())
         func.assert_called_once()
 
-    async def test_to_thread_concurrent(self):
+    def test_to_thread_concurrent(self):
         func = mock.Mock()
 
-        futs = []
-        for _ in range(10):
-            fut = asyncio.to_thread(func)
-            futs.append(fut)
-        await asyncio.gather(*futs)
+        async def main():
+            futs = []
+            for _ in range(10):
+                fut = asyncio.to_thread(func)
+                futs.append(fut)
+            await asyncio.gather(*futs)
 
+        self.loop.run_until_complete(main())
         self.assertEqual(func.call_count, 10)
 
-    async def test_to_thread_args_kwargs(self):
+    def test_to_thread_args_kwargs(self):
         # Unlike run_in_executor(), to_thread() should directly accept kwargs.
         func = mock.Mock()
 
-        await asyncio.to_thread(func, 'test', something=True)
+        async def main():
+            await asyncio.to_thread(func, 'test', something=True)
 
+        self.loop.run_until_complete(main())
         func.assert_called_once_with('test', something=True)
 
-    async def test_to_thread_contextvars(self):
+    def test_to_thread_contextvars(self):
         test_ctx = ContextVar('test_ctx')
 
         def get_ctx():
             return test_ctx.get()
 
-        test_ctx.set('parrot')
-        result = await asyncio.to_thread(get_ctx)
+        async def main():
+            test_ctx.set('parrot')
+            return await asyncio.to_thread(get_ctx)
 
+        result = self.loop.run_until_complete(main())
         self.assertEqual(result, 'parrot')