code: def test_run_calls_normalize_metadata(self, test_files_path):
      bytestream = ByteStream(
          data=b"test", meta={"author": "test_author", "language": "en"}
      )
  
      converter = MarkdownToDocument()
  
      with patch(
          "haystack.components.converters.markdown.normalize_metadata"
      ) as normalize_metadata, patch(
          "haystack.components.converters.markdown.MarkdownIt"
      ):
          converter.run(
              sources=[
                  bytestream,
                  test_files_path / "markdown" / "sample.md",
              ],
              meta={"language": "it"},
          )
  
      # check that the metadata normalizer is called properly
      normalize_metadata.assert_called_with(
          meta={"language": "it"}, sources_count=2
      )
  
file_path: haystack/test/components/converters/test_markdown_to_document.py
imports: import logging
  from unittest.mock import patch
  import pytest
  from haystack.components.converters.markdown import MarkdownToDocument
  from haystack.dataclasses import ByteStream
label_desc: Use image node_id 4 for calling the TestMarkdownToDocument obj's underlying member method code with example usage: obj.test_run_calls_normalize_metadata(test_files_path) without return types