diff --git a/requirements-test.txt b/requirements-test.txt
--- a/requirements-test.txt
+++ b/requirements-test.txt
@@ -1,5 +1,4 @@
 pytest < 7.0.0  # v7.0.0 removed _pytest.tmpdir.TempdirFactory, which is used by some of the pytest plugins we use
-pytest-asyncio
 pytest-mock
 requests_mock[fixture] >= 1.9
 requests_toolbelt
diff --git a/swh/objstorage/backends/azure.py b/swh/objstorage/backends/azure.py
--- a/swh/objstorage/backends/azure.py
+++ b/swh/objstorage/backends/azure.py
@@ -27,6 +27,7 @@
     compute_hash,
     decompressors,
 )
+from swh.objstorage.utils import call_async
 
 
 def get_container_url(
@@ -76,16 +77,6 @@
     return f"https://{account_name}.blob.core.windows.net/{container_name}?{signature}"
 
 
-def call_async(f, *args):
-    """Calls an async coroutine from a synchronous function."""
-    loop = asyncio.new_event_loop()
-    try:
-        return loop.run_until_complete(f(*args))
-    finally:
-        loop.run_until_complete(loop.shutdown_asyncgens())
-        loop.close()
-
-
 class AzureCloudObjStorage(ObjStorage):
     """ObjStorage backend for Azure blob storage accounts.
 
diff --git a/swh/objstorage/tests/test_objstorage_winery.py b/swh/objstorage/tests/test_objstorage_winery.py
--- a/swh/objstorage/tests/test_objstorage_winery.py
+++ b/swh/objstorage/tests/test_objstorage_winery.py
@@ -20,6 +20,7 @@
     Throttler,
 )
 from swh.objstorage.factory import get_objstorage
+from swh.objstorage.utils import call_async
 
 from .winery_benchmark import Bench, work
 from .winery_testing_helpers import PoolHelper, SharedBaseHelper
@@ -207,8 +208,7 @@
     assert work("ro", winery.args) == "ro"
 
 
-@pytest.mark.asyncio
-async def test_winery_bench_real(pytestconfig, postgresql, ceph_pool):
+def test_winery_bench_real(pytestconfig, postgresql, ceph_pool):
     dsn = (
         f"postgres://{postgresql.info.user}"
         f":@{postgresql.info.host}:{postgresql.info.port}"
@@ -227,12 +227,11 @@
         "throttle_read": pytestconfig.getoption("--winery-bench-throttle-read"),
         "throttle_write": pytestconfig.getoption("--winery-bench-throttle-write"),
     }
-    count = await Bench(kwargs).run()
+    count = call_async(Bench(kwargs).run)
     assert count > 0
 
 
-@pytest.mark.asyncio
-async def test_winery_bench_fake(pytestconfig, mocker):
+def test_winery_bench_fake(pytestconfig, mocker):
     kwargs = {
         "rw_workers": pytestconfig.getoption("--winery-bench-rw-workers"),
         "ro_workers": pytestconfig.getoption("--winery-bench-ro-workers"),
@@ -244,7 +243,7 @@
         return kind
 
     mocker.patch("swh.objstorage.tests.winery_benchmark.Worker.run", side_effect=run)
-    assert await Bench(kwargs).run() == kwargs["rw_workers"] + kwargs["ro_workers"]
+    assert call_async(Bench(kwargs).run) == kwargs["rw_workers"] + kwargs["ro_workers"]
 
 
 def test_winery_leaky_bucket_tick(mocker):
diff --git a/swh/objstorage/utils.py b/swh/objstorage/utils.py
new file mode 100644
--- /dev/null
+++ b/swh/objstorage/utils.py
@@ -0,0 +1,16 @@
+# Copyright (C) 2021  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+import asyncio
+
+
+def call_async(f, *args):
+    """Calls an async coroutine from a synchronous function."""
+    loop = asyncio.new_event_loop()
+    try:
+        return loop.run_until_complete(f(*args))
+    finally:
+        loop.run_until_complete(loop.shutdown_asyncgens())
+        loop.close()