fix(RemoteStore): avoid listing all objects in remote store in empty() method (zarr-developers#2312)

* fix(RemoteStore): avoid listing all objects in remote store in empty() method

* use ls instead of walk

Author: jhamman

src/zarr/storage/remote.py

@@ -94,7 +94,9 @@ async def clear(self) -> None:
             pass
 
     async def empty(self) -> bool:
-        return not await self.fs._find(self.path, withdirs=True)
+        # TODO: it would be nice if we didn't have to list all keys here
+        # it should be possible to stop after the first key is discovered
+        return not await self.fs._ls(self.path)
 
     def with_mode(self, mode: AccessModeLiteral) -> Self:
         return type(self)(

tests/v3/test_store/test_remote.py

@@ -135,14 +135,13 @@ def test_store_repr(self, store: RemoteStore) -> None:
         assert str(store) == "<RemoteStore(S3FileSystem, test)>"
 
     def test_store_supports_writes(self, store: RemoteStore) -> None:
-        assert True
+        assert store.supports_writes
 
-    @pytest.mark.xfail
     def test_store_supports_partial_writes(self, store: RemoteStore) -> None:
-        raise AssertionError
+        assert not store.supports_partial_writes
 
     def test_store_supports_listing(self, store: RemoteStore) -> None:
-        assert True
+        assert store.supports_listing
 
     async def test_remote_store_from_uri(
         self, store: RemoteStore, store_kwargs: dict[str, str | bool]