docstr: Test empty text and a text which might get reduced to empty text by removing dashes
code: def test_empty_text(self, pipeline):
      """
      Test empty text and a text which might get reduced to empty text by removing dashes
      """
      doc = pipeline("")
      assert len(doc.sentences) == 0
  
      doc = pipeline("--")
      assert len(doc.sentences) == 1
  
file_path: stanza/stanza/tests/pipeline/test_pipeline_sentiment_processor.py
imports: import pytest
  import stanza
  from stanza.utils.conll import CoNLL
  from stanza.models.common.doc import Document
  from stanza.tests import *
label_desc: Use image node_id 4 for calling the TestSentimentPipeline obj's underlying member method code with example usage: obj.test_empty_text(pipeline) without return types