class_docstr: Test InMemoryDocumentStore's specific features
class_docstr_tok: ["Test","InMemoryDocumentStore","'s","specific","features"]
code: def test_bm25_retrieval_empty_query(
      self, document_store: InMemoryDocumentStore
  ):
      # Tests if the bm25_retrieval method returns a document when the query is an empty string.
      docs = [
          Document(content="Hello world"),
          Document(content="Haystack supports multiple languages"),
      ]
      document_store.write_documents(docs)
      with pytest.raises(
          ValueError, match="Query should be a non-empty string"
      ):
          document_store.bm25_retrieval(query="", top_k=1)
  
imports: import logging
  from unittest.mock import patch
  import pandas
  import pytest
  from haystack import Document
  from haystack.document_stores.errors import DocumentStoreError, DuplicateDocumentError
  from haystack.document_stores.in_memory import InMemoryDocumentStore
  from haystack.testing.document_store import DocumentStoreBaseTests
label_desc: Use image node_id 8 for calling the TestMemoryDocumentStore obj's underlying member method code with example usage: obj.test_bm25_retrieval_empty_query(document_store) without return types