class_docstr: Tests vocabulary related operations.
      
docstr: Tests the _make_defaultdict function.
          
docstr_tok: ["Tests","the","_make_defaultdict","function","."]
code: def test_make_defaultdict(self):
      """Tests the _make_defaultdict function."""
      keys = ["word", "词"]
      values = [0, 1]
      default_value = -1
  
      dict_ = vocabulary._make_defaultdict(keys, values, default_value)
  
      self.assertEqual(len(dict_), 2)
      self.assertEqual(dict_["word"], 0)
      self.assertEqual(dict_["词"], 1)
      self.assertEqual(dict_["sth_else"], -1)
  
imports: import tempfile
  import tensorflow
  from texar.tf.data import vocabulary
label_desc: Use image node_id 1 for calling the VocabularyTest obj's underlying member method code with example usage: obj.test_make_defaultdict() without return types