code: def test_copy_metadata(self):
      splitter = DocumentSplitter(split_by="word", split_length=10)
      documents = [
          Document(content="Text.", meta={"name": "doc 0"}),
          Document(content="Text.", meta={"name": "doc 1"}),
      ]
      result = splitter.run(documents=documents)
      assert len(result["documents"]) == 2
      assert result["documents"][0].id != result["documents"][1].id
      for doc, split_doc in zip(documents, result["documents"]):
          assert doc.meta.items() <= split_doc.meta.items()
          assert split_doc.content == "Text."
  
file_path: haystack/test/components/preprocessors/test_document_splitter.py
imports: import pytest
  from haystack import Document
  from haystack.components.preprocessors import DocumentSplitter
label_desc: Use image node_id 13 for calling the TestDocumentSplitter obj's underlying member method code with example usage: obj.test_copy_metadata() without return types