Don't trim paths in list_file if class initialized with no path

Previously, if `S3SubdirectoryFileStore` was initialized with no path other than the s3 bucket
ie. `s3://bucket-name`
The returned paths would have the first letter trimmed incorrectly

If self.path is not set we do not need to trim the returned paths

This change, ensures that the returned paths are not incorrectly trimmed

tests/storage/test_storage.py

@@ -175,7 +175,6 @@ def test_list_files(self, get_boto_bucket):
             Prefix="folder/a/b"
         )
 
-    @pytest.mark.xfail(reason="Expose bug when listing files with no bucket path")
     @mock.patch.object(storage.S3FileStore, "_get_boto_bucket")
     def test_list_files_no_path(self, get_boto_bucket):
         get_boto_bucket.return_value = mock.Mock(

xocto/storage/storage.py

@@ -1013,10 +1013,12 @@ def list_s3_keys_page(
         return objects, next_token
 
     def list_files(self, namespace: str = "") -> Iterable[str]:
+        path_trim = 0
         if self.path:
+            path_trim = len(self.path) + 1
             namespace = os.path.join(self.path, namespace)
         full_paths = super().list_files(namespace)
-        yield from (path[len(self.path) + 1 :] for path in full_paths)
+        yield from (path[path_trim:] for path in full_paths)
 
     def copy(self, *, s3_object: S3Object, destination: str) -> S3Object:
         if self.path: