Change the default vocab file name from 'vocab' to 'vocab.txt', if vocab flag is specified.

PiperOrigin-RevId: 361484017

Author: lintian06

tensorflow_examples/lite/model_maker/core/task/custom_model.py

@@ -126,7 +126,7 @@ def export(self,
              export_dir,
              tflite_filename='model.tflite',
              label_filename='labels.txt',
-             vocab_filename='vocab',
+             vocab_filename='vocab.txt',
              saved_model_filename='saved_model',
              tfjs_folder_name='tfjs',
              export_format=None,

tensorflow_examples/lite/model_maker/core/task/question_answer_test.py

@@ -101,7 +101,7 @@ def _test_f1_score(self, model, validation_data, threshold):
     self.assertGreaterEqual(metric['final_f1'], threshold)
 
   def _test_export_vocab(self, model):
-    vocab_output_file = os.path.join(self.get_temp_dir(), 'vocab')
+    vocab_output_file = os.path.join(self.get_temp_dir(), 'vocab.txt')
     model.export(self.get_temp_dir(), export_format=ExportFormat.VOCAB)
 
     self.assertTrue(os.path.isfile(vocab_output_file))

tensorflow_examples/lite/model_maker/core/task/text_classifier_test.py

@@ -170,7 +170,7 @@ def _test_export_labels(self, model):
     self.assertEqual(labels, ['neg', 'pos'])
 
   def _test_export_vocab(self, model):
-    vocab_output_file = os.path.join(self.get_temp_dir(), 'vocab')
+    vocab_output_file = os.path.join(self.get_temp_dir(), 'vocab.txt')
     model.export(self.get_temp_dir(), export_format=ExportFormat.VOCAB)
 
     word_index = self._load_vocab(vocab_output_file)