code: def test_cn_text_field(self):
      self.assertRaises(ValueError, CnTextField, {})
  
      # test mask
      test_field = CnTextField("小明去上海")
  
      # test pos tag only the return format is correct, not the label
      pos_tag = test_field.pos_tags()
      self.assertEqual(pos_tag[-1][-1] + 1, len(test_field.tokens))
      self.assertEqual(pos_tag[0][1], 0)
      for tag in pos_tag:
          self.assertTrue([str, int, int], [type(i) for i in tag])
  
      # test ner only the return format is correct, not the label
      ner, ner_label = test_field.ner()
      self.assertEqual(len(ner_label), len(test_field.tokens))
      for tag in ner:
          self.assertTrue(
              [str, int, int] == [type(k) for k in tag]
              and tag[1] <= tag[2]
          )
  
imports: import unittest
  from textflint.input.component.field.cn_text_field import *
label_desc: Use image node_id 1 for calling the TestCnTextField obj's underlying member method code with example usage: obj.test_cn_text_field() without return types