code: def test_transformation(self):
      sent1 = "The quick brown fox jumps over the lazy dog ."
      data_sample = SASample({"x": sent1, "y": "negative"})
  
      # test wrong model
      self.assertRaises(ValueError, WordCase, "random little")
  
      # test model
      test_case = WordCase()
      self.assertTrue(
          test_case.case_type in ["upper", "lower", "title", "random"]
      )
  
      # test lower
      self.assertEqual(
          [word.lower() for word in data_sample.get_words("x")],
          WordCase("lower").transform(data_sample)[0].get_words("x"),
      )
  
      # test upper
      self.assertEqual(
          [word.upper() for word in data_sample.get_words("x")],
          WordCase("upper").transform(data_sample)[0].get_words("x"),
      )
  
      # test title
      self.assertEqual(
          [word.title() for word in data_sample.get_words("x")],
          WordCase("title").transform(data_sample)[0].get_words("x"),
      )
  
      # test special case
      special_sample = SASample({"x": "", "y": "negative"})
      self.assertEqual(
          "",
          WordCase("lower").transform(special_sample)[0].get_text("x"),
      )
      special_sample = SASample(
          {"x": "~!@#$%^7890\"'", "y": "negative"}
      )
      self.assertEqual(
          "~!@#$%^7890\"'",
          WordCase("lower").transform(special_sample)[0].get_text("x"),
      )
  
imports: import unittest
  from textflint.input.component.sample import SASample
  from textflint.generation.transformation.UT.word_case import WordCase
label_desc: Use image node_id 1 for calling the TestWordWordCase obj's underlying member method code with example usage: obj.test_transformation() without return types