diff --git a/packages/autorest.python/test/vanilla/legacy/AcceptanceTests/asynctests/test_complex.py b/packages/autorest.python/test/vanilla/legacy/AcceptanceTests/asynctests/test_complex.py
index 6876a3e2b45..e46396e20fe 100644
--- a/packages/autorest.python/test/vanilla/legacy/AcceptanceTests/asynctests/test_complex.py
+++ b/packages/autorest.python/test/vanilla/legacy/AcceptanceTests/asynctests/test_complex.py
@@ -536,6 +536,7 @@ async def test_polymorphism_get_and_put_missing_discriminator(self, client):
         assert dot_salmon.fish_type == "DotSalmon"
         assert dot_salmon.location == "sweden"
 
+    @pytest.mark.asyncio
     async def test_pass_in_api_version(self, client):
         assert client._config.api_version == "2016-02-29"
         async with AutoRestComplexTestService(base_url="http://localhost:3000", api_version="2021-10-01") as client: