diff --git a/test/asynchronous/test_gridfs_bucket.py b/test/asynchronous/test_gridfs_bucket.py
new file mode 100644
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--- /dev/null
+++ b/test/asynchronous/test_gridfs_bucket.py
@@ -0,0 +1,574 @@
+#
+# Copyright 2015-present MongoDB, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Tests for the gridfs package."""
+from __future__ import annotations
+
+import asyncio
+import datetime
+import itertools
+import sys
+import threading
+import time
+from io import BytesIO
+from test.asynchronous.helpers import ConcurrentRunner
+from unittest.mock import patch
+
+sys.path[0:0] = [""]
+
+from test.asynchronous import AsyncIntegrationTest, async_client_context, unittest
+from test.utils import async_joinall, joinall, one
+
+import gridfs
+from bson.binary import Binary
+from bson.int64 import Int64
+from bson.objectid import ObjectId
+from bson.son import SON
+from gridfs.errors import CorruptGridFile, NoFile
+from pymongo.asynchronous.mongo_client import AsyncMongoClient
+from pymongo.errors import (
+    ConfigurationError,
+    NotPrimaryError,
+    ServerSelectionTimeoutError,
+    WriteConcernError,
+)
+from pymongo.read_preferences import ReadPreference
+
+_IS_SYNC = False
+
+
+class JustWrite(ConcurrentRunner):
+    def __init__(self, gfs, num):
+        super().__init__()
+        self.gfs = gfs
+        self.num = num
+        self.daemon = True
+
+    async def run(self):
+        for _ in range(self.num):
+            file = self.gfs.open_upload_stream("test")
+            await file.write(b"hello")
+            await file.close()
+
+
+class JustRead(ConcurrentRunner):
+    def __init__(self, gfs, num, results):
+        super().__init__()
+        self.gfs = gfs
+        self.num = num
+        self.results = results
+        self.daemon = True
+
+    async def run(self):
+        for _ in range(self.num):
+            file = await self.gfs.open_download_stream_by_name("test")
+            data = await file.read()
+            self.results.append(data)
+            assert data == b"hello"
+
+
+class TestGridfs(AsyncIntegrationTest):
+    fs: gridfs.AsyncGridFSBucket
+    alt: gridfs.AsyncGridFSBucket
+
+    async def asyncSetUp(self):
+        await super().asyncSetUp()
+        self.fs = gridfs.AsyncGridFSBucket(self.db)
+        self.alt = gridfs.AsyncGridFSBucket(self.db, bucket_name="alt")
+        await self.cleanup_colls(
+            self.db.fs.files, self.db.fs.chunks, self.db.alt.files, self.db.alt.chunks
+        )
+
+    async def test_basic(self):
+        oid = await self.fs.upload_from_stream("test_filename", b"hello world")
+        self.assertEqual(b"hello world", await (await self.fs.open_download_stream(oid)).read())
+        self.assertEqual(1, await self.db.fs.files.count_documents({}))
+        self.assertEqual(1, await self.db.fs.chunks.count_documents({}))
+
+        await self.fs.delete(oid)
+        with self.assertRaises(NoFile):
+            await self.fs.open_download_stream(oid)
+        self.assertEqual(0, await self.db.fs.files.count_documents({}))
+        self.assertEqual(0, await self.db.fs.chunks.count_documents({}))
+
+    async def test_multi_chunk_delete(self):
+        self.assertEqual(0, await self.db.fs.files.count_documents({}))
+        self.assertEqual(0, await self.db.fs.chunks.count_documents({}))
+        gfs = gridfs.AsyncGridFSBucket(self.db)
+        oid = await gfs.upload_from_stream("test_filename", b"hello", chunk_size_bytes=1)
+        self.assertEqual(1, await self.db.fs.files.count_documents({}))
+        self.assertEqual(5, await self.db.fs.chunks.count_documents({}))
+        await gfs.delete(oid)
+        self.assertEqual(0, await self.db.fs.files.count_documents({}))
+        self.assertEqual(0, await self.db.fs.chunks.count_documents({}))
+
+    async def test_empty_file(self):
+        oid = await self.fs.upload_from_stream("test_filename", b"")
+        self.assertEqual(b"", await (await self.fs.open_download_stream(oid)).read())
+        self.assertEqual(1, await self.db.fs.files.count_documents({}))
+        self.assertEqual(0, await self.db.fs.chunks.count_documents({}))
+
+        raw = await self.db.fs.files.find_one()
+        assert raw is not None
+        self.assertEqual(0, raw["length"])
+        self.assertEqual(oid, raw["_id"])
+        self.assertTrue(isinstance(raw["uploadDate"], datetime.datetime))
+        self.assertEqual(255 * 1024, raw["chunkSize"])
+        self.assertNotIn("md5", raw)
+
+    async def test_corrupt_chunk(self):
+        files_id = await self.fs.upload_from_stream("test_filename", b"foobar")
+        await self.db.fs.chunks.update_one(
+            {"files_id": files_id}, {"$set": {"data": Binary(b"foo", 0)}}
+        )
+        try:
+            out = await self.fs.open_download_stream(files_id)
+            with self.assertRaises(CorruptGridFile):
+                await out.read()
+
+            out = await self.fs.open_download_stream(files_id)
+            with self.assertRaises(CorruptGridFile):
+                await out.readline()
+        finally:
+            await self.fs.delete(files_id)
+
+    async def test_upload_ensures_index(self):
+        chunks = self.db.fs.chunks
+        files = self.db.fs.files
+        # Ensure the collections are removed.
+        await chunks.drop()
+        await files.drop()
+        await self.fs.upload_from_stream("filename", b"junk")
+
+        self.assertTrue(
+            any(
+                info.get("key") == [("files_id", 1), ("n", 1)]
+                for info in (await chunks.index_information()).values()
+            )
+        )
+        self.assertTrue(
+            any(
+                info.get("key") == [("filename", 1), ("uploadDate", 1)]
+                for info in (await files.index_information()).values()
+            )
+        )
+
+    async def test_ensure_index_shell_compat(self):
+        files = self.db.fs.files
+        for i, j in itertools.combinations_with_replacement([1, 1.0, Int64(1)], 2):
+            # Create the index with different numeric types (as might be done
+            # from the mongo shell).
+            shell_index = [("filename", i), ("uploadDate", j)]
+            await self.db.command(
+                "createIndexes",
+                files.name,
+                indexes=[{"key": SON(shell_index), "name": "filename_1.0_uploadDate_1.0"}],
+            )
+
+            # No error.
+            await self.fs.upload_from_stream("filename", b"data")
+
+            self.assertTrue(
+                any(
+                    info.get("key") == [("filename", 1), ("uploadDate", 1)]
+                    for info in (await files.index_information()).values()
+                )
+            )
+            await files.drop()
+
+    async def test_alt_collection(self):
+        oid = await self.alt.upload_from_stream("test_filename", b"hello world")
+        self.assertEqual(b"hello world", await (await self.alt.open_download_stream(oid)).read())
+        self.assertEqual(1, await self.db.alt.files.count_documents({}))
+        self.assertEqual(1, await self.db.alt.chunks.count_documents({}))
+
+        await self.alt.delete(oid)
+        with self.assertRaises(NoFile):
+            await self.alt.open_download_stream(oid)
+        self.assertEqual(0, await self.db.alt.files.count_documents({}))
+        self.assertEqual(0, await self.db.alt.chunks.count_documents({}))
+
+        with self.assertRaises(NoFile):
+            await self.alt.open_download_stream("foo")
+        await self.alt.upload_from_stream("foo", b"hello world")
+        self.assertEqual(
+            b"hello world", await (await self.alt.open_download_stream_by_name("foo")).read()
+        )
+
+        await self.alt.upload_from_stream("mike", b"")
+        await self.alt.upload_from_stream("test", b"foo")
+        await self.alt.upload_from_stream("hello world", b"")
+
+        self.assertEqual(
+            {"mike", "test", "hello world", "foo"},
+            {k["filename"] for k in await self.db.alt.files.find().to_list()},
+        )
+
+    async def test_threaded_reads(self):
+        await self.fs.upload_from_stream("test", b"hello")
+
+        threads = []
+        results: list = []
+        for i in range(10):
+            threads.append(JustRead(self.fs, 10, results))
+            await threads[i].start()
+
+        await async_joinall(threads)
+
+        self.assertEqual(100 * [b"hello"], results)
+
+    async def test_threaded_writes(self):
+        threads = []
+        for i in range(10):
+            threads.append(JustWrite(self.fs, 10))
+            await threads[i].start()
+
+        await async_joinall(threads)
+
+        fstr = await self.fs.open_download_stream_by_name("test")
+        self.assertEqual(await fstr.read(), b"hello")
+
+        # Should have created 100 versions of 'test' file
+        self.assertEqual(100, await self.db.fs.files.count_documents({"filename": "test"}))
+
+    async def test_get_last_version(self):
+        one = await self.fs.upload_from_stream("test", b"foo")
+        await asyncio.sleep(0.01)
+        two = self.fs.open_upload_stream("test")
+        await two.write(b"bar")
+        await two.close()
+        await asyncio.sleep(0.01)
+        two = two._id
+        three = await self.fs.upload_from_stream("test", b"baz")
+
+        self.assertEqual(b"baz", await (await self.fs.open_download_stream_by_name("test")).read())
+        await self.fs.delete(three)
+        self.assertEqual(b"bar", await (await self.fs.open_download_stream_by_name("test")).read())
+        await self.fs.delete(two)
+        self.assertEqual(b"foo", await (await self.fs.open_download_stream_by_name("test")).read())
+        await self.fs.delete(one)
+        with self.assertRaises(NoFile):
+            await self.fs.open_download_stream_by_name("test")
+
+    async def test_get_version(self):
+        await self.fs.upload_from_stream("test", b"foo")
+        await asyncio.sleep(0.01)
+        await self.fs.upload_from_stream("test", b"bar")
+        await asyncio.sleep(0.01)
+        await self.fs.upload_from_stream("test", b"baz")
+        await asyncio.sleep(0.01)
+
+        self.assertEqual(
+            b"foo", await (await self.fs.open_download_stream_by_name("test", revision=0)).read()
+        )
+        self.assertEqual(
+            b"bar", await (await self.fs.open_download_stream_by_name("test", revision=1)).read()
+        )
+        self.assertEqual(
+            b"baz", await (await self.fs.open_download_stream_by_name("test", revision=2)).read()
+        )
+
+        self.assertEqual(
+            b"baz", await (await self.fs.open_download_stream_by_name("test", revision=-1)).read()
+        )
+        self.assertEqual(
+            b"bar", await (await self.fs.open_download_stream_by_name("test", revision=-2)).read()
+        )
+        self.assertEqual(
+            b"foo", await (await self.fs.open_download_stream_by_name("test", revision=-3)).read()
+        )
+
+        with self.assertRaises(NoFile):
+            await self.fs.open_download_stream_by_name("test", revision=3)
+        with self.assertRaises(NoFile):
+            await self.fs.open_download_stream_by_name("test", revision=-4)
+
+    async def test_upload_from_stream(self):
+        oid = await self.fs.upload_from_stream(
+            "test_file", BytesIO(b"hello world"), chunk_size_bytes=1
+        )
+        self.assertEqual(11, await self.db.fs.chunks.count_documents({}))
+        self.assertEqual(b"hello world", await (await self.fs.open_download_stream(oid)).read())
+
+    async def test_upload_from_stream_with_id(self):
+        oid = ObjectId()
+        await self.fs.upload_from_stream_with_id(
+            oid, "test_file_custom_id", BytesIO(b"custom id"), chunk_size_bytes=1
+        )
+        self.assertEqual(b"custom id", await (await self.fs.open_download_stream(oid)).read())
+
+    @patch("gridfs.asynchronous.grid_file._UPLOAD_BUFFER_CHUNKS", 3)
+    @async_client_context.require_failCommand_fail_point
+    async def test_upload_bulk_write_error(self):
+        # Test BulkWriteError from insert_many is converted to an insert_one style error.
+        expected_wce = {
+            "code": 100,
+            "codeName": "UnsatisfiableWriteConcern",
+            "errmsg": "Not enough data-bearing nodes",
+        }
+        cause_wce = {
+            "configureFailPoint": "failCommand",
+            "mode": {"times": 2},
+            "data": {"failCommands": ["insert"], "writeConcernError": expected_wce},
+        }
+        gin = self.fs.open_upload_stream("test_file", chunk_size_bytes=1)
+        async with self.fail_point(cause_wce):
+            # Assert we raise WriteConcernError, not BulkWriteError.
+            with self.assertRaises(WriteConcernError):
+                await gin.write(b"hello world")
+        # 3 chunks were uploaded.
+        self.assertEqual(3, await self.db.fs.chunks.count_documents({"files_id": gin._id}))
+        await gin.abort()
+
+    @patch("gridfs.asynchronous.grid_file._UPLOAD_BUFFER_CHUNKS", 10)
+    async def test_upload_batching(self):
+        async with self.fs.open_upload_stream("test_file", chunk_size_bytes=1) as gin:
+            await gin.write(b"s" * (10 - 1))
+            # No chunks were uploaded yet.
+            self.assertEqual(0, await self.db.fs.chunks.count_documents({"files_id": gin._id}))
+            await gin.write(b"s")
+            # All chunks were uploaded since we hit the _UPLOAD_BUFFER_CHUNKS limit.
+            self.assertEqual(10, await self.db.fs.chunks.count_documents({"files_id": gin._id}))
+
+    async def test_open_upload_stream(self):
+        gin = self.fs.open_upload_stream("from_stream")
+        await gin.write(b"from stream")
+        await gin.close()
+        self.assertEqual(b"from stream", await (await self.fs.open_download_stream(gin._id)).read())
+
+    async def test_open_upload_stream_with_id(self):
+        oid = ObjectId()
+        gin = self.fs.open_upload_stream_with_id(oid, "from_stream_custom_id")
+        await gin.write(b"from stream with custom id")
+        await gin.close()
+        self.assertEqual(
+            b"from stream with custom id", await (await self.fs.open_download_stream(oid)).read()
+        )
+
+    async def test_missing_length_iter(self):
+        # Test fix that guards against PHP-237
+        await self.fs.upload_from_stream("empty", b"")
+        doc = await self.db.fs.files.find_one({"filename": "empty"})
+        assert doc is not None
+        doc.pop("length")
+        await self.db.fs.files.replace_one({"_id": doc["_id"]}, doc)
+        fstr = await self.fs.open_download_stream_by_name("empty")
+
+        async def iterate_file(grid_file):
+            async for _ in grid_file:
+                pass
+            return True
+
+        self.assertTrue(await iterate_file(fstr))
+
+    async def test_gridfs_lazy_connect(self):
+        client = await self.async_single_client(
+            "badhost", connect=False, serverSelectionTimeoutMS=0
+        )
+        cdb = client.db
+        gfs = gridfs.AsyncGridFSBucket(cdb)
+        with self.assertRaises(ServerSelectionTimeoutError):
+            await gfs.delete(0)
+
+        gfs = gridfs.AsyncGridFSBucket(cdb)
+        with self.assertRaises(ServerSelectionTimeoutError):
+            await gfs.upload_from_stream("test", b"")  # Still no connection.
+
+    async def test_gridfs_find(self):
+        await self.fs.upload_from_stream("two", b"test2")
+        await asyncio.sleep(0.01)
+        await self.fs.upload_from_stream("two", b"test2+")
+        await asyncio.sleep(0.01)
+        await self.fs.upload_from_stream("one", b"test1")
+        await asyncio.sleep(0.01)
+        await self.fs.upload_from_stream("two", b"test2++")
+        files = self.db.fs.files
+        self.assertEqual(3, await files.count_documents({"filename": "two"}))
+        self.assertEqual(4, await files.count_documents({}))
+        cursor = self.fs.find(
+            {}, no_cursor_timeout=False, sort=[("uploadDate", -1)], skip=1, limit=2
+        )
+        gout = await cursor.next()
+        self.assertEqual(b"test1", await gout.read())
+        await cursor.rewind()
+        gout = await cursor.next()
+        self.assertEqual(b"test1", await gout.read())
+        gout = await cursor.next()
+        self.assertEqual(b"test2+", await gout.read())
+        with self.assertRaises(StopAsyncIteration):
+            await cursor.next()
+        await cursor.close()
+        self.assertRaises(TypeError, self.fs.find, {}, {"_id": True})
+
+    async def test_grid_in_non_int_chunksize(self):
+        # Lua, and perhaps other buggy AsyncGridFS clients, store size as a float.
+        data = b"data"
+        await self.fs.upload_from_stream("f", data)
+        await self.db.fs.files.update_one({"filename": "f"}, {"$set": {"chunkSize": 100.0}})
+
+        self.assertEqual(data, await (await self.fs.open_download_stream_by_name("f")).read())
+
+    async def test_unacknowledged(self):
+        # w=0 is prohibited.
+        with self.assertRaises(ConfigurationError):
+            gridfs.AsyncGridFSBucket((await self.async_rs_or_single_client(w=0)).pymongo_test)
+
+    async def test_rename(self):
+        _id = await self.fs.upload_from_stream("first_name", b"testing")
+        self.assertEqual(
+            b"testing", await (await self.fs.open_download_stream_by_name("first_name")).read()
+        )
+
+        await self.fs.rename(_id, "second_name")
+        with self.assertRaises(NoFile):
+            await self.fs.open_download_stream_by_name("first_name")
+        self.assertEqual(
+            b"testing", await (await self.fs.open_download_stream_by_name("second_name")).read()
+        )
+
+    @patch("gridfs.asynchronous.grid_file._UPLOAD_BUFFER_SIZE", 5)
+    async def test_abort(self):
+        gin = self.fs.open_upload_stream("test_filename", chunk_size_bytes=5)
+        await gin.write(b"test1")
+        await gin.write(b"test2")
+        await gin.write(b"test3")
+        self.assertEqual(3, await self.db.fs.chunks.count_documents({"files_id": gin._id}))
+        await gin.abort()
+        self.assertTrue(gin.closed)
+        with self.assertRaises(ValueError):
+            await gin.write(b"test4")
+        self.assertEqual(0, await self.db.fs.chunks.count_documents({"files_id": gin._id}))
+
+    async def test_download_to_stream(self):
+        file1 = BytesIO(b"hello world")
+        # Test with one chunk.
+        oid = await self.fs.upload_from_stream("one_chunk", file1)
+        self.assertEqual(1, await self.db.fs.chunks.count_documents({}))
+        file2 = BytesIO()
+        await self.fs.download_to_stream(oid, file2)
+        file1.seek(0)
+        file2.seek(0)
+        self.assertEqual(file1.read(), file2.read())
+
+        # Test with many chunks.
+        await self.db.drop_collection("fs.files")
+        await self.db.drop_collection("fs.chunks")
+        file1.seek(0)
+        oid = await self.fs.upload_from_stream("many_chunks", file1, chunk_size_bytes=1)
+        self.assertEqual(11, await self.db.fs.chunks.count_documents({}))
+        file2 = BytesIO()
+        await self.fs.download_to_stream(oid, file2)
+        file1.seek(0)
+        file2.seek(0)
+        self.assertEqual(file1.read(), file2.read())
+
+    async def test_download_to_stream_by_name(self):
+        file1 = BytesIO(b"hello world")
+        # Test with one chunk.
+        _ = await self.fs.upload_from_stream("one_chunk", file1)
+        self.assertEqual(1, await self.db.fs.chunks.count_documents({}))
+        file2 = BytesIO()
+        await self.fs.download_to_stream_by_name("one_chunk", file2)
+        file1.seek(0)
+        file2.seek(0)
+        self.assertEqual(file1.read(), file2.read())
+
+        # Test with many chunks.
+        await self.db.drop_collection("fs.files")
+        await self.db.drop_collection("fs.chunks")
+        file1.seek(0)
+        await self.fs.upload_from_stream("many_chunks", file1, chunk_size_bytes=1)
+        self.assertEqual(11, await self.db.fs.chunks.count_documents({}))
+
+        file2 = BytesIO()
+        await self.fs.download_to_stream_by_name("many_chunks", file2)
+        file1.seek(0)
+        file2.seek(0)
+        self.assertEqual(file1.read(), file2.read())
+
+    async def test_md5(self):
+        gin = self.fs.open_upload_stream("no md5")
+        await gin.write(b"no md5 sum")
+        await gin.close()
+        self.assertIsNone(gin.md5)
+
+        gout = await self.fs.open_download_stream(gin._id)
+        self.assertIsNone(gout.md5)
+
+        gin = self.fs.open_upload_stream_with_id(ObjectId(), "also no md5")
+        await gin.write(b"also no md5 sum")
+        await gin.close()
+        self.assertIsNone(gin.md5)
+
+        gout = await self.fs.open_download_stream(gin._id)
+        self.assertIsNone(gout.md5)
+
+
+class TestGridfsBucketReplicaSet(AsyncIntegrationTest):
+    @async_client_context.require_secondaries_count(1)
+    async def asyncSetUp(self):
+        await super().asyncSetUp()
+
+    @classmethod
+    @async_client_context.require_connection
+    async def asyncTearDownClass(cls):
+        await async_client_context.client.drop_database("gfsbucketreplica")
+
+    async def test_gridfs_replica_set(self):
+        rsc = await self.async_rs_client(
+            w=async_client_context.w, read_preference=ReadPreference.SECONDARY
+        )
+
+        gfs = gridfs.AsyncGridFSBucket(rsc.gfsbucketreplica, "gfsbucketreplicatest")
+        oid = await gfs.upload_from_stream("test_filename", b"foo")
+        content = await (await gfs.open_download_stream(oid)).read()
+        self.assertEqual(b"foo", content)
+
+    async def test_gridfs_secondary(self):
+        secondary_host, secondary_port = one(await self.client.secondaries)
+        secondary_connection = await self.async_single_client(
+            secondary_host, secondary_port, read_preference=ReadPreference.SECONDARY
+        )
+
+        # Should detect it's connected to secondary and not attempt to
+        # create index
+        gfs = gridfs.AsyncGridFSBucket(
+            secondary_connection.gfsbucketreplica, "gfsbucketsecondarytest"
+        )
+
+        # This won't detect secondary, raises error
+        with self.assertRaises(NotPrimaryError):
+            await gfs.upload_from_stream("test_filename", b"foo")
+
+    async def test_gridfs_secondary_lazy(self):
+        # Should detect it's connected to secondary and not attempt to
+        # create index.
+        secondary_host, secondary_port = one(await self.client.secondaries)
+        client = await self.async_single_client(
+            secondary_host, secondary_port, read_preference=ReadPreference.SECONDARY, connect=False
+        )
+
+        # Still no connection.
+        gfs = gridfs.AsyncGridFSBucket(client.gfsbucketreplica, "gfsbucketsecondarylazytest")
+
+        # Connects, doesn't create index.
+        with self.assertRaises(NoFile):
+            await gfs.open_download_stream_by_name("test_filename")
+        with self.assertRaises(NotPrimaryError):
+            await gfs.upload_from_stream("test_filename", b"data")
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/test/test_gridfs_bucket.py b/test/test_gridfs_bucket.py
index 0af4dce811..e7486cb237 100644
--- a/test/test_gridfs_bucket.py
+++ b/test/test_gridfs_bucket.py
@@ -16,12 +16,14 @@
 """Tests for the gridfs package."""
 from __future__ import annotations
 
+import asyncio
 import datetime
 import itertools
 import sys
 import threading
 import time
 from io import BytesIO
+from test.helpers import ConcurrentRunner
 from unittest.mock import patch
 
 sys.path[0:0] = [""]
@@ -44,10 +46,12 @@
 from pymongo.read_preferences import ReadPreference
 from pymongo.synchronous.mongo_client import MongoClient
 
+_IS_SYNC = True
 
-class JustWrite(threading.Thread):
+
+class JustWrite(ConcurrentRunner):
     def __init__(self, gfs, num):
-        threading.Thread.__init__(self)
+        super().__init__()
         self.gfs = gfs
         self.num = num
         self.daemon = True
@@ -59,9 +63,9 @@ def run(self):
             file.close()
 
 
-class JustRead(threading.Thread):
+class JustRead(ConcurrentRunner):
     def __init__(self, gfs, num, results):
-        threading.Thread.__init__(self)
+        super().__init__()
         self.gfs = gfs
         self.num = num
         self.results = results
@@ -89,12 +93,13 @@ def setUp(self):
 
     def test_basic(self):
         oid = self.fs.upload_from_stream("test_filename", b"hello world")
-        self.assertEqual(b"hello world", self.fs.open_download_stream(oid).read())
+        self.assertEqual(b"hello world", (self.fs.open_download_stream(oid)).read())
         self.assertEqual(1, self.db.fs.files.count_documents({}))
         self.assertEqual(1, self.db.fs.chunks.count_documents({}))
 
         self.fs.delete(oid)
-        self.assertRaises(NoFile, self.fs.open_download_stream, oid)
+        with self.assertRaises(NoFile):
+            self.fs.open_download_stream(oid)
         self.assertEqual(0, self.db.fs.files.count_documents({}))
         self.assertEqual(0, self.db.fs.chunks.count_documents({}))
 
@@ -111,7 +116,7 @@ def test_multi_chunk_delete(self):
 
     def test_empty_file(self):
         oid = self.fs.upload_from_stream("test_filename", b"")
-        self.assertEqual(b"", self.fs.open_download_stream(oid).read())
+        self.assertEqual(b"", (self.fs.open_download_stream(oid)).read())
         self.assertEqual(1, self.db.fs.files.count_documents({}))
         self.assertEqual(0, self.db.fs.chunks.count_documents({}))
 
@@ -128,10 +133,12 @@ def test_corrupt_chunk(self):
         self.db.fs.chunks.update_one({"files_id": files_id}, {"$set": {"data": Binary(b"foo", 0)}})
         try:
             out = self.fs.open_download_stream(files_id)
-            self.assertRaises(CorruptGridFile, out.read)
+            with self.assertRaises(CorruptGridFile):
+                out.read()
 
             out = self.fs.open_download_stream(files_id)
-            self.assertRaises(CorruptGridFile, out.readline)
+            with self.assertRaises(CorruptGridFile):
+                out.readline()
         finally:
             self.fs.delete(files_id)
 
@@ -146,13 +153,13 @@ def test_upload_ensures_index(self):
         self.assertTrue(
             any(
                 info.get("key") == [("files_id", 1), ("n", 1)]
-                for info in chunks.index_information().values()
+                for info in (chunks.index_information()).values()
             )
         )
         self.assertTrue(
             any(
                 info.get("key") == [("filename", 1), ("uploadDate", 1)]
-                for info in files.index_information().values()
+                for info in (files.index_information()).values()
             )
         )
 
@@ -174,25 +181,27 @@ def test_ensure_index_shell_compat(self):
             self.assertTrue(
                 any(
                     info.get("key") == [("filename", 1), ("uploadDate", 1)]
-                    for info in files.index_information().values()
+                    for info in (files.index_information()).values()
                 )
             )
             files.drop()
 
     def test_alt_collection(self):
         oid = self.alt.upload_from_stream("test_filename", b"hello world")
-        self.assertEqual(b"hello world", self.alt.open_download_stream(oid).read())
+        self.assertEqual(b"hello world", (self.alt.open_download_stream(oid)).read())
         self.assertEqual(1, self.db.alt.files.count_documents({}))
         self.assertEqual(1, self.db.alt.chunks.count_documents({}))
 
         self.alt.delete(oid)
-        self.assertRaises(NoFile, self.alt.open_download_stream, oid)
+        with self.assertRaises(NoFile):
+            self.alt.open_download_stream(oid)
         self.assertEqual(0, self.db.alt.files.count_documents({}))
         self.assertEqual(0, self.db.alt.chunks.count_documents({}))
 
-        self.assertRaises(NoFile, self.alt.open_download_stream, "foo")
+        with self.assertRaises(NoFile):
+            self.alt.open_download_stream("foo")
         self.alt.upload_from_stream("foo", b"hello world")
-        self.assertEqual(b"hello world", self.alt.open_download_stream_by_name("foo").read())
+        self.assertEqual(b"hello world", (self.alt.open_download_stream_by_name("foo")).read())
 
         self.alt.upload_from_stream("mike", b"")
         self.alt.upload_from_stream("test", b"foo")
@@ -200,7 +209,7 @@ def test_alt_collection(self):
 
         self.assertEqual(
             {"mike", "test", "hello world", "foo"},
-            {k["filename"] for k in list(self.db.alt.files.find())},
+            {k["filename"] for k in self.db.alt.files.find().to_list()},
         )
 
     def test_threaded_reads(self):
@@ -240,13 +249,14 @@ def test_get_last_version(self):
         two = two._id
         three = self.fs.upload_from_stream("test", b"baz")
 
-        self.assertEqual(b"baz", self.fs.open_download_stream_by_name("test").read())
+        self.assertEqual(b"baz", (self.fs.open_download_stream_by_name("test")).read())
         self.fs.delete(three)
-        self.assertEqual(b"bar", self.fs.open_download_stream_by_name("test").read())
+        self.assertEqual(b"bar", (self.fs.open_download_stream_by_name("test")).read())
         self.fs.delete(two)
-        self.assertEqual(b"foo", self.fs.open_download_stream_by_name("test").read())
+        self.assertEqual(b"foo", (self.fs.open_download_stream_by_name("test")).read())
         self.fs.delete(one)
-        self.assertRaises(NoFile, self.fs.open_download_stream_by_name, "test")
+        with self.assertRaises(NoFile):
+            self.fs.open_download_stream_by_name("test")
 
     def test_get_version(self):
         self.fs.upload_from_stream("test", b"foo")
@@ -256,28 +266,30 @@ def test_get_version(self):
         self.fs.upload_from_stream("test", b"baz")
         time.sleep(0.01)
 
-        self.assertEqual(b"foo", self.fs.open_download_stream_by_name("test", revision=0).read())
-        self.assertEqual(b"bar", self.fs.open_download_stream_by_name("test", revision=1).read())
-        self.assertEqual(b"baz", self.fs.open_download_stream_by_name("test", revision=2).read())
+        self.assertEqual(b"foo", (self.fs.open_download_stream_by_name("test", revision=0)).read())
+        self.assertEqual(b"bar", (self.fs.open_download_stream_by_name("test", revision=1)).read())
+        self.assertEqual(b"baz", (self.fs.open_download_stream_by_name("test", revision=2)).read())
 
-        self.assertEqual(b"baz", self.fs.open_download_stream_by_name("test", revision=-1).read())
-        self.assertEqual(b"bar", self.fs.open_download_stream_by_name("test", revision=-2).read())
-        self.assertEqual(b"foo", self.fs.open_download_stream_by_name("test", revision=-3).read())
+        self.assertEqual(b"baz", (self.fs.open_download_stream_by_name("test", revision=-1)).read())
+        self.assertEqual(b"bar", (self.fs.open_download_stream_by_name("test", revision=-2)).read())
+        self.assertEqual(b"foo", (self.fs.open_download_stream_by_name("test", revision=-3)).read())
 
-        self.assertRaises(NoFile, self.fs.open_download_stream_by_name, "test", revision=3)
-        self.assertRaises(NoFile, self.fs.open_download_stream_by_name, "test", revision=-4)
+        with self.assertRaises(NoFile):
+            self.fs.open_download_stream_by_name("test", revision=3)
+        with self.assertRaises(NoFile):
+            self.fs.open_download_stream_by_name("test", revision=-4)
 
     def test_upload_from_stream(self):
         oid = self.fs.upload_from_stream("test_file", BytesIO(b"hello world"), chunk_size_bytes=1)
         self.assertEqual(11, self.db.fs.chunks.count_documents({}))
-        self.assertEqual(b"hello world", self.fs.open_download_stream(oid).read())
+        self.assertEqual(b"hello world", (self.fs.open_download_stream(oid)).read())
 
     def test_upload_from_stream_with_id(self):
         oid = ObjectId()
         self.fs.upload_from_stream_with_id(
             oid, "test_file_custom_id", BytesIO(b"custom id"), chunk_size_bytes=1
         )
-        self.assertEqual(b"custom id", self.fs.open_download_stream(oid).read())
+        self.assertEqual(b"custom id", (self.fs.open_download_stream(oid)).read())
 
     @patch("gridfs.synchronous.grid_file._UPLOAD_BUFFER_CHUNKS", 3)
     @client_context.require_failCommand_fail_point
@@ -316,14 +328,14 @@ def test_open_upload_stream(self):
         gin = self.fs.open_upload_stream("from_stream")
         gin.write(b"from stream")
         gin.close()
-        self.assertEqual(b"from stream", self.fs.open_download_stream(gin._id).read())
+        self.assertEqual(b"from stream", (self.fs.open_download_stream(gin._id)).read())
 
     def test_open_upload_stream_with_id(self):
         oid = ObjectId()
         gin = self.fs.open_upload_stream_with_id(oid, "from_stream_custom_id")
         gin.write(b"from stream with custom id")
         gin.close()
-        self.assertEqual(b"from stream with custom id", self.fs.open_download_stream(oid).read())
+        self.assertEqual(b"from stream with custom id", (self.fs.open_download_stream(oid)).read())
 
     def test_missing_length_iter(self):
         # Test fix that guards against PHP-237
@@ -345,12 +357,12 @@ def test_gridfs_lazy_connect(self):
         client = self.single_client("badhost", connect=False, serverSelectionTimeoutMS=0)
         cdb = client.db
         gfs = gridfs.GridFSBucket(cdb)
-        self.assertRaises(ServerSelectionTimeoutError, gfs.delete, 0)
+        with self.assertRaises(ServerSelectionTimeoutError):
+            gfs.delete(0)
 
         gfs = gridfs.GridFSBucket(cdb)
-        self.assertRaises(
-            ServerSelectionTimeoutError, gfs.upload_from_stream, "test", b""
-        )  # Still no connection.
+        with self.assertRaises(ServerSelectionTimeoutError):
+            gfs.upload_from_stream("test", b"")  # Still no connection.
 
     def test_gridfs_find(self):
         self.fs.upload_from_stream("two", b"test2")
@@ -366,14 +378,15 @@ def test_gridfs_find(self):
         cursor = self.fs.find(
             {}, no_cursor_timeout=False, sort=[("uploadDate", -1)], skip=1, limit=2
         )
-        gout = next(cursor)
+        gout = cursor.next()
         self.assertEqual(b"test1", gout.read())
         cursor.rewind()
-        gout = next(cursor)
+        gout = cursor.next()
         self.assertEqual(b"test1", gout.read())
-        gout = next(cursor)
+        gout = cursor.next()
         self.assertEqual(b"test2+", gout.read())
-        self.assertRaises(StopIteration, cursor.__next__)
+        with self.assertRaises(StopIteration):
+            cursor.next()
         cursor.close()
         self.assertRaises(TypeError, self.fs.find, {}, {"_id": True})
 
@@ -383,20 +396,21 @@ def test_grid_in_non_int_chunksize(self):
         self.fs.upload_from_stream("f", data)
         self.db.fs.files.update_one({"filename": "f"}, {"$set": {"chunkSize": 100.0}})
 
-        self.assertEqual(data, self.fs.open_download_stream_by_name("f").read())
+        self.assertEqual(data, (self.fs.open_download_stream_by_name("f")).read())
 
     def test_unacknowledged(self):
         # w=0 is prohibited.
         with self.assertRaises(ConfigurationError):
-            gridfs.GridFSBucket(self.rs_or_single_client(w=0).pymongo_test)
+            gridfs.GridFSBucket((self.rs_or_single_client(w=0)).pymongo_test)
 
     def test_rename(self):
         _id = self.fs.upload_from_stream("first_name", b"testing")
-        self.assertEqual(b"testing", self.fs.open_download_stream_by_name("first_name").read())
+        self.assertEqual(b"testing", (self.fs.open_download_stream_by_name("first_name")).read())
 
         self.fs.rename(_id, "second_name")
-        self.assertRaises(NoFile, self.fs.open_download_stream_by_name, "first_name")
-        self.assertEqual(b"testing", self.fs.open_download_stream_by_name("second_name").read())
+        with self.assertRaises(NoFile):
+            self.fs.open_download_stream_by_name("first_name")
+        self.assertEqual(b"testing", (self.fs.open_download_stream_by_name("second_name")).read())
 
     @patch("gridfs.synchronous.grid_file._UPLOAD_BUFFER_SIZE", 5)
     def test_abort(self):
@@ -407,7 +421,8 @@ def test_abort(self):
         self.assertEqual(3, self.db.fs.chunks.count_documents({"files_id": gin._id}))
         gin.abort()
         self.assertTrue(gin.closed)
-        self.assertRaises(ValueError, gin.write, b"test4")
+        with self.assertRaises(ValueError):
+            gin.write(b"test4")
         self.assertEqual(0, self.db.fs.chunks.count_documents({"files_id": gin._id}))
 
     def test_download_to_stream(self):
@@ -490,7 +505,7 @@ def test_gridfs_replica_set(self):
 
         gfs = gridfs.GridFSBucket(rsc.gfsbucketreplica, "gfsbucketreplicatest")
         oid = gfs.upload_from_stream("test_filename", b"foo")
-        content = gfs.open_download_stream(oid).read()
+        content = (gfs.open_download_stream(oid)).read()
         self.assertEqual(b"foo", content)
 
     def test_gridfs_secondary(self):
@@ -504,7 +519,8 @@ def test_gridfs_secondary(self):
         gfs = gridfs.GridFSBucket(secondary_connection.gfsbucketreplica, "gfsbucketsecondarytest")
 
         # This won't detect secondary, raises error
-        self.assertRaises(NotPrimaryError, gfs.upload_from_stream, "test_filename", b"foo")
+        with self.assertRaises(NotPrimaryError):
+            gfs.upload_from_stream("test_filename", b"foo")
 
     def test_gridfs_secondary_lazy(self):
         # Should detect it's connected to secondary and not attempt to
@@ -518,8 +534,10 @@ def test_gridfs_secondary_lazy(self):
         gfs = gridfs.GridFSBucket(client.gfsbucketreplica, "gfsbucketsecondarylazytest")
 
         # Connects, doesn't create index.
-        self.assertRaises(NoFile, gfs.open_download_stream_by_name, "test_filename")
-        self.assertRaises(NotPrimaryError, gfs.upload_from_stream, "test_filename", b"data")
+        with self.assertRaises(NoFile):
+            gfs.open_download_stream_by_name("test_filename")
+        with self.assertRaises(NotPrimaryError):
+            gfs.upload_from_stream("test_filename", b"data")
 
 
 if __name__ == "__main__":
diff --git a/tools/synchro.py b/tools/synchro.py
index bc1fcd7869..e4f70a0b0e 100644
--- a/tools/synchro.py
+++ b/tools/synchro.py
@@ -216,6 +216,7 @@ def async_only_test(f: str) -> bool:
     "test_examples.py",
     "test_grid_file.py",
     "test_gridfs.py",
+    "test_gridfs_bucket.py",
     "test_gridfs_spec.py",
     "test_heartbeat_monitoring.py",
     "test_index_management.py",