only do output_past=True for language generation in bart

tests/test_modeling_bart.py

@@ -64,7 +64,6 @@ class ModelTester:
         self.eos_token_id = 2
         self.pad_token_id = 1
         self.bos_token_id = 0
-        self.output_past = True
         torch.manual_seed(0)
 
     def prepare_config_and_inputs_for_common(self):
@@ -86,7 +85,6 @@ class ModelTester:
             eos_token_ids=self.eos_token_id,
             bos_token_id=self.bos_token_id,
             pad_token_id=self.pad_token_id,
-            output_past=self.output_past,
         )
         inputs_dict = prepare_bart_inputs_dict(config, input_ids)
         return config, inputs_dict

tests/test_modeling_common.py

@@ -628,6 +628,9 @@ class ModelTesterMixin:
             "input_ids", None
         )  # TODO (PVP): ugly workaround to make code work for t5 for the moment - has to changed when t5 is fixed.
 
+        if self.is_encoder_decoder:
+            config.output_past = True  # needed for Bart TODO: might have to update for other encoder-decoder models
+
         for model_class in self.all_generative_model_classes:
             model = model_class(config)
             model.to(torch_device)