code: def test_embed_meta(self, mocked_sort, mocked_sigmoid):
      mocked_sort.return_value = (None, torch.tensor([0]))
      mocked_sigmoid.return_value = torch.tensor([0])
      embedder = TransformersSimilarityRanker(
          model="model",
          meta_fields_to_embed=["meta_field"],
          embedding_separator="\n",
      )
      embedder._model = MagicMock()
      embedder.tokenizer = MagicMock()
  
      documents = [
          Document(
              content=f"document number {i}",
              meta={"meta_field": f"meta_value {i}"},
          )
          for i in range(5)
      ]
  
      embedder.run(query="test", documents=documents)
  
      embedder.tokenizer.assert_called_once_with(
          [
              ["test", "meta_value 0\ndocument number 0"],
              ["test", "meta_value 1\ndocument number 1"],
              ["test", "meta_value 2\ndocument number 2"],
              ["test", "meta_value 3\ndocument number 3"],
              ["test", "meta_value 4\ndocument number 4"],
          ],
          padding=True,
          truncation=True,
          return_tensors="pt",
      )
  
file_path: haystack/test/components/rankers/test_transformers_similarity.py
imports: from unittest.mock import MagicMock, patch
  import pytest
  import torch
  from transformers.modeling_outputs import SequenceClassifierOutput
  from haystack import Document, ComponentError
  from haystack.components.rankers.transformers_similarity import TransformersSimilarityRanker
label_desc: Use image node_id 5 for calling the TestSimilarityRanker obj's underlying member method code with example usage: obj.test_embed_meta(mocked_sort, mocked_sigmoid) without return types