Fix (beta): truncate embedding queries for small chunk size (#13028)

src/paperless_ai/tests/test_ai_indexing.py

@@ -137,6 +137,16 @@ def test_get_rag_prompt_helper_uses_context_setting() -> None:
     assert prompt_helper.context_window == 4096
 
 
+def test_truncate_embedding_query_returns_single_chunk() -> None:
+    content = " ".join(f"word{i}" for i in range(200))
+
+    result = indexing.truncate_embedding_query(content, chunk_size=32)
+
+    assert result
+    assert result != content
+    assert "word199" not in result
+
+
 @pytest.mark.django_db
 def test_update_llm_index(
     temp_llm_index_dir: Path,
@@ -393,6 +403,42 @@ def test_query_similar_documents(
         assert result == mock_filtered_docs
 
 
+@override_settings(
+    LLM_EMBEDDING_BACKEND="huggingface",
+    LLM_EMBEDDING_CHUNK_SIZE=32,
+    LLM_BACKEND="ollama",
+)
+def test_query_similar_documents_truncates_query_to_embedding_chunk_size(
+    temp_llm_index_dir: Path,
+    real_document: Document,
+) -> None:
+    real_document.content = " ".join(f"word{i}" for i in range(200))
+    with (
+        patch("paperless_ai.indexing.load_or_build_index") as mock_load_or_build_index,
+        patch(
+            "paperless_ai.indexing.llm_index_exists",
+        ) as mock_vector_store_exists,
+        patch("llama_index.core.retrievers.VectorIndexRetriever") as mock_retriever_cls,
+        patch("paperless_ai.indexing.Document.objects.filter") as mock_filter,
+        patch("paperless_ai.indexing.truncate_content") as mock_truncate_content,
+    ):
+        mock_vector_store_exists.return_value = True
+        mock_load_or_build_index.return_value = MagicMock()
+        mock_truncate_content.return_value = "wrong helper"
+
+        mock_retriever = MagicMock()
+        mock_retriever.retrieve.return_value = []
+        mock_retriever_cls.return_value = mock_retriever
+        mock_filter.return_value = []
+
+        indexing.query_similar_documents(real_document, top_k=3)
+
+        mock_truncate_content.assert_not_called()
+        query_text = mock_retriever.retrieve.call_args.args[0]
+        assert query_text
+        assert "word199" not in query_text
+
+
 @pytest.mark.django_db
 def test_query_similar_documents_triggers_update_when_index_missing(
     temp_llm_index_dir: Path,