code: def test_indexing_empty_list_of_files(self):
      document_store = InMemoryDocumentStore()
      pipeline = build_indexing_pipeline(document_store=document_store)
      result = pipeline.run(files=[])
      assert result == {"documents_written": 0}
  
file_path: haystack/test/pipelines/test_indexing_pipeline.py
imports: import os
  import pytest
  from haystack.pipeline_utils.indexing import build_indexing_pipeline
  from haystack.document_stores.in_memory import InMemoryDocumentStore
label_desc: Use image node_id 5 for calling the TestIndexingPipeline obj's underlying member method code with example usage: obj.test_indexing_empty_list_of_files() without return types