code: def test_unsupported_split_by(self):
      with pytest.raises(
          ValueError,
          match="split_by must be one of 'word', 'sentence' or 'passage'.",
      ):
          DocumentSplitter(split_by="unsupported")
  
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 4 for calling the TestDocumentSplitter obj's underlying member method code with example usage: obj.test_unsupported_split_by() without return types