Add test for _apply_descriptions_sync to cover skip branch

tests/test_rebuild.py

@@ -970,6 +970,34 @@ async def test_rebuild_descriptions_raises_when_blob_is_missing(
                 pass
 
 
+def test_apply_descriptions_sync_skips_pictures_without_descriptions():
+    """_apply_descriptions_sync skips pictures not in the descriptions dict."""
+    from unittest.mock import MagicMock
+
+    from haiku.rag.client.rebuild import _apply_descriptions_sync
+
+    pic_with = MagicMock()
+    pic_with.self_ref = "pic-1"
+    pic_with.meta = None
+
+    pic_without = MagicMock()
+    pic_without.self_ref = "pic-2"
+
+    docling_doc = MagicMock()
+    docling_doc.pictures = [pic_with, pic_without]
+    docling_doc.model_dump_json.return_value = "{}"
+    docling_doc.version = "1.0"
+
+    doc = MagicMock()
+
+    descriptions = {"pic-1": "A red square."}
+    n = _apply_descriptions_sync(docling_doc, doc, descriptions)
+
+    assert n == 1
+    assert pic_with.meta is not None
+    assert pic_with.meta.description.text == "A red square."
+
+
 async def _add_chunk(client: HaikuRAG, vector: list[float]) -> str:
     """Insert a chunk row directly, bypassing the embedder."""
     record = client.store.ChunkRecord(