code: def test_run_with_concatenate_join_mode_and_duplicate_documents(self):
      joiner = DocumentJoiner()
      documents_1 = [
          Document(content="a", score=0.3),
          Document(content="b"),
          Document(content="c"),
      ]
      documents_2 = [
          Document(content="a", score=0.2),
          Document(content="a"),
          Document(content="f", meta={"key": "value"}),
      ]
      output = joiner.run([documents_1, documents_2])
      assert len(output["documents"]) == 4
      assert sorted(
          documents_1 + [documents_2[-1]], key=lambda d: d.id
      ) == sorted(output["documents"], key=lambda d: d.id)
  
file_path: haystack/test/components/joiners/test_document_joiner.py
imports: import logging
  import pytest
  from haystack import Document
  from haystack.components.joiners.document_joiner import DocumentJoiner
label_desc: Use image node_id 8 for calling the TestDocumentJoiner obj's underlying member method code with example usage: obj.test_run_with_concatenate_join_mode_and_duplicate_documents() without return types