Review comments

Author: dcherian

src/zarr/storage/_local.py

@@ -214,6 +214,12 @@ async def delete_dir(self, prefix: str) -> None:
         path = self.root / prefix
         if path.is_dir():
             shutil.rmtree(path)
+        elif path.is_file():
+            raise ValueError(f"delete_dir was passed a {prefix=!r} that is a file")
+        else:
+            # Non-existent directory
+            # This path is tested by test_group:test_create_creates_parents for one
+            pass
 
     async def exists(self, key: str) -> bool:
         # docstring inherited