docstr: Test that the component correctly handles files with non specified mime types.
code: def test_unlisted_extensions(self, test_files_path):
      """
      Test that the component correctly handles files with non specified mime types.
      """
      file_paths = [
          test_files_path / "txt" / "doc_1.txt",
          test_files_path / "audio" / "ignored.mp3",
          test_files_path
          / "audio"
          / "this is the content of the document.wav",
      ]
      router = FileTypeRouter(mime_types=["text/plain"])
      output = router.run(sources=file_paths)
      assert len(output["text/plain"]) == 1
      assert "mp3" not in output
      assert len(output["unclassified"]) == 2
      assert str(output["unclassified"][0]).endswith("ignored.mp3")
      assert str(output["unclassified"][1]).endswith(
          "this is the content of the document.wav"
      )
  
file_path: haystack/test/components/routers/test_file_router.py
imports: import sys
  import pytest
  from haystack.components.routers.file_type_router import FileTypeRouter
  from haystack.dataclasses import ByteStream
label_desc: Use image node_id 5 for calling the TestFileTypeRouter obj's underlying member method code with example usage: obj.test_unlisted_extensions(test_files_path) without return types