Fix incorrect group attribute update tests

Author: moradology

tests/test_group.py

@@ -604,7 +604,10 @@ def test_group_update_attributes(store: Store, zarr_format: ZarrFormat) -> None:
     assert group.attrs == attrs
     new_attrs = {"bar": 100}
     new_group = group.update_attributes(new_attrs)
-    assert new_group.attrs == new_attrs
+
+    updated_attrs = attrs.copy()
+    updated_attrs.update(new_attrs)
+    assert new_group.attrs == updated_attrs
 
 
 async def test_group_update_attributes_async(store: Store, zarr_format: ZarrFormat) -> None:
@@ -1008,7 +1011,9 @@ async def test_asyncgroup_update_attributes(store: Store, zarr_format: ZarrForma
     )
 
     agroup_new_attributes = await agroup.update_attributes(attributes_new)
-    assert agroup_new_attributes.attrs == attributes_new
+    attributes_updated = attributes_old.copy()
+    attributes_updated.update(attributes_new)
+    assert agroup_new_attributes.attrs == attributes_updated
 
 
 @pytest.mark.parametrize("store", ["local"], indirect=["store"])