code: def test_run(self):
      embedder = SentenceTransformersTextEmbedder(model="model")
      embedder.embedding_backend = MagicMock()
      embedder.embedding_backend.embed = (
          lambda x, **kwargs: np.random.rand(len(x), 16).tolist()
      )
  
      text = "a nice text to embed"
  
      result = embedder.run(text=text)
      embedding = result["embedding"]
  
      assert isinstance(embedding, list)
      assert all(isinstance(el, float) for el in embedding)
  
file_path: haystack/test/components/embedders/test_sentence_transformers_text_embedder.py
imports: from unittest.mock import patch, MagicMock
  import pytest
  import numpy
  from haystack.components.embedders.sentence_transformers_text_embedder import SentenceTransformersTextEmbedder
label_desc: Use image node_id 8 for calling the TestSentenceTransformersTextEmbedder obj's underlying member method code with example usage: obj.test_run() without return types