Expose get_config() on ModelTesters (#12812)

* Expose get_config() on ModelTesters

* Typo

tests/test_modeling_roberta.py

@@ -17,7 +17,7 @@
 import unittest
 from copy import deepcopy
 
-from transformers import is_torch_available
+from transformers import RobertaConfig, is_torch_available
 from transformers.testing_utils import TestCasePlus, require_torch, slow, torch_device
 
 from .test_configuration_common import ConfigTester
@@ -29,7 +29,6 @@ if is_torch_available():
     import torch
 
     from transformers import (
-        RobertaConfig,
         RobertaForCausalLM,
         RobertaForMaskedLM,
         RobertaForMultipleChoice,
@@ -94,7 +93,12 @@ class RobertaModelTester:
             token_labels = ids_tensor([self.batch_size, self.seq_length], self.num_labels)
             choice_labels = ids_tensor([self.batch_size], self.num_choices)
 
-        config = RobertaConfig(
+        config = self.get_config()
+
+        return config, input_ids, token_type_ids, input_mask, sequence_labels, token_labels, choice_labels
+
+    def get_config(self):
+        return RobertaConfig(
             vocab_size=self.vocab_size,
             hidden_size=self.hidden_size,
             num_hidden_layers=self.num_hidden_layers,
@@ -108,8 +112,6 @@ class RobertaModelTester:
             initializer_range=self.initializer_range,
         )
 
-        return config, input_ids, token_type_ids, input_mask, sequence_labels, token_labels, choice_labels
-
     def prepare_config_and_inputs_for_decoder(self):
         (
             config,