fix id if only a single structure is provided

Author: eimrek

src/optimade_maker/convert.py

@@ -321,6 +321,9 @@ def _set_unique_entry_ids(entry_ids: list[str]) -> list[str]:
 
     """
 
+    if len(entry_ids) == 1:
+        return [os.path.splitext(os.path.basename(entry_ids[0]))[0]]
+
     new_ids: list[str] = list(entry_ids)
 
     def _strip_common_path(ids, from_back=False):

tests/test_convert.py

@@ -158,3 +158,8 @@ def test_unique_id_generator():
         "set2/3.xyz",
         "set2/4.xyz",
     ]
+
+    entry_ids = [
+        "data/structures/1.cif",
+    ]
+    assert _set_unique_entry_ids(entry_ids) == ["1"]