class_docstr: Tests the helper functions.
class_docstr_tok: ["Tests","the","helper","functions","."]
docstr: Test that tuples of indices are correctly mapped to words.
docstr_tok: ["Test","that","tuples","of","indices","are","correctly","mapped","to","words","."]
code: def test_tuple_to_word(self, tuple, expected_word):
      """Test that tuples of indices are correctly mapped to words."""
      assert _tuple_to_word(tuple) == expected_word
  
imports: import pytest
  import numpy
  from pennylane import numpy
  import pennylane
  from pennylane.templates.subroutines.arbitrary_unitary import _all_pauli_words_but_identity, _tuple_to_word, _n_k_gray_code
label_desc: Use image node_id 3 for calling the TestHelpers obj's underlying member method code with example usage: obj.test_tuple_to_word(tuple, expected_word) without return types