code: def test_run_with_merge_join_mode(self):
      joiner = DocumentJoiner(join_mode="merge", weights=[1.5, 0.5])
      documents_1 = [
          Document(content="a", score=1.0),
          Document(content="b", score=2.0),
      ]
      documents_2 = [
          Document(content="a", score=0.5),
          Document(content="b", score=3.0),
          Document(content="f", score=4.0, meta={"key": "value"}),
      ]
      output = joiner.run([documents_1, documents_2])
      assert len(output["documents"]) == 3
      expected_document_ids = [
          doc.id
          for doc in [
              Document(content="a", score=1.25),
              Document(content="b", score=2.25),
              Document(content="f", score=4.0, meta={"key": "value"}),
          ]
      ]
      assert all(
          doc.id in expected_document_ids for doc in output["documents"]
      )
  
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 9 for calling the TestDocumentJoiner obj's underlying member method code with example usage: obj.test_run_with_merge_join_mode() without return types