code: def test_bleu_empty_functional():
      """Test that bleu returns 0 when no input is provided."""
      hyp = [[]]
      ref = [[[]]]
      assert bleu_score(hyp, ref) == tensor(0.0)
  
imports: from functools import partial
  from typing import Any
  import pytest
  from nltk.translate.bleu_score import SmoothingFunction, corpus_bleu
  from torch import tensor
  from torchmetrics.functional.text.bleu import bleu_score
  from torchmetrics.text.bleu import BLEUScore
  from unittests.text.helpers import TextTester
  from unittests.text.inputs import _inputs_multiple_references
label_desc: Use image node_id 2 for calling a global function with example usage: test_bleu_empty_functional() without return types