code: def test_empty_string(self):
      classifier = TextLanguageRouter()
      result = classifier.run(text="")
      assert result == {"unmatched": ""}
  
file_path: haystack/test/components/routers/test_text_language_router.py
imports: import logging
  import pytest
  from haystack import Document
  from haystack.components.routers import TextLanguageRouter
label_desc: Use image node_id 3 for calling the TestTextLanguageRouter obj's underlying member method code with example usage: obj.test_empty_string() without return types