docstr: Test that the component ignores files with no extension.
code: def test_no_extension(self, test_files_path):
      """
      Test that the component ignores files with no extension.
      """
      file_paths = [
          test_files_path / "txt" / "doc_1.txt",
          test_files_path / "txt" / "doc_2",
          test_files_path / "txt" / "doc_2.txt",
      ]
      router = FileTypeRouter(mime_types=["text/plain"])
      output = router.run(sources=file_paths)
      assert len(output["text/plain"]) == 2
      assert len(output["unclassified"]) == 1
  
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 6 for calling the TestFileTypeRouter obj's underlying member method code with example usage: obj.test_no_extension(test_files_path) without return types