[Bart] enable test_torchscript, update test_tie_weights (#5457)

* Passing all but one torchscript test

* Style

* move comment

* remove unneeded assert

tests/test_modeling_bart.py

@@ -120,7 +120,7 @@ class BARTModelTest(ModelTesterMixin, unittest.TestCase):
     is_encoder_decoder = True
     # TODO(SS): fix the below in a separate PR
     test_pruning = False
-    test_torchscript = False
+    test_torchscript = True
     test_head_masking = False
     test_resize_embeddings = True  # This requires inputs_dict['input_ids']
     test_missing_keys = False  # because BartForConditionalGeneration and BartModel now have identical state_dict
@@ -133,7 +133,6 @@ class BARTModelTest(ModelTesterMixin, unittest.TestCase):
         self.config_tester.run_common_tests()
 
     def test_initialization_more(self):
-        # (config, input_ids, token_type_ids, input_mask, *unused) = \
         config, inputs_dict = self.model_tester.prepare_config_and_inputs_for_common()
         model = BartModel(config)
         model.to(torch_device)

tests/test_modeling_common.py

@@ -612,15 +612,11 @@ class ModelTesterMixin:
             if model_not_tied.get_output_embeddings() is None:
                 continue
 
-            params_not_tied = list(model_not_tied.parameters())
-
             config_tied = copy.deepcopy(config)
             config_tied.torchscript = False
             model_tied = model_class(config_tied)
             params_tied = list(model_tied.parameters())
-
             # Check that the embedding layer and decoding layer are the same in size and in value
-            self.assertGreater(len(params_not_tied), len(params_tied))
             # self.assertTrue(check_same_values(embeddings, decoding))
 
             # # Check that after modification, they remain the same.
@@ -638,7 +634,6 @@ class ModelTesterMixin:
             # Check that after resize they remain tied.
             model_tied.resize_token_embeddings(config.vocab_size + 10)
             params_tied_2 = list(model_tied.parameters())
-            self.assertGreater(len(params_not_tied), len(params_tied))
             self.assertEqual(len(params_tied_2), len(params_tied))
 
             # decoding.weight.data.mul_(20)