diff --git a/xarray/tests/test_backends.py b/xarray/tests/test_backends.py
index 18f84e2df42..4c04841db8d 100644
--- a/xarray/tests/test_backends.py
+++ b/xarray/tests/test_backends.py
@@ -2877,7 +2877,7 @@ def test_avoid_excess_metadata_calls(self) -> None:
 
         import zarr
 
-        ds = xr.Dataset(data_vars={"test": (("Z", ), np.array([123]).reshape(1))})
+        ds = xr.Dataset(data_vars={"test": (("Z",), np.array([123]).reshape(1))})
 
         # The call to retrieve metadata performs a group lookup. We patch Group.__getitem__
         # so that we can inspect calls to this method - specifically count of calls.