Replace (TF)CommonTestCases for modeling with a mixin.

I suspect the wrapper classes were created in order to prevent the
abstract base class (TF)CommonModelTester from being included in test
discovery and running, because that would fail.

I solved this by replacing the abstract base class with a mixin.

Code changes are just de-indenting and automatic reformattings
performed by black to use the extra line space.

templates/adding_a_new_model/tests/test_modeling_tf_xxx.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import XxxConfig, is_tf_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_tf_common import TFCommonTestCases, ids_tensor
+from .test_modeling_tf_common import TFModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_tf, slow
 
 
@@ -32,7 +34,7 @@ if is_tf_available():
 
 
 @require_tf
-class TFXxxModelTest(TFCommonTestCases.TFCommonModelTester):
+class TFXxxModelTest(TFModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (
         (

templates/adding_a_new_model/tests/test_modeling_xxx.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import is_torch_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_common import CommonTestCases, ids_tensor
+from .test_modeling_common import ModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_torch, slow, torch_device
 
 
@@ -34,7 +36,7 @@ if is_torch_available():
 
 
 @require_torch
-class XxxModelTest(CommonTestCases.CommonModelTester):
+class XxxModelTest(ModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (
         (XxxModel, XxxForMaskedLM, XxxForQuestionAnswering, XxxForSequenceClassification, XxxForTokenClassification)

tests/test_modeling_albert.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import is_torch_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_common import CommonTestCases, ids_tensor
+from .test_modeling_common import ModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_torch, slow, torch_device
 
 
@@ -33,7 +35,7 @@ if is_torch_available():
 
 
 @require_torch
-class AlbertModelTest(CommonTestCases.CommonModelTester):
+class AlbertModelTest(ModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (AlbertModel, AlbertForMaskedLM) if is_torch_available() else ()
 

tests/test_modeling_bert.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import is_torch_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_common import CommonTestCases, floats_tensor, ids_tensor
+from .test_modeling_common import ModelTesterMixin, floats_tensor, ids_tensor
 from .utils import CACHE_DIR, require_torch, slow, torch_device
 
 
@@ -37,7 +39,7 @@ if is_torch_available():
 
 
 @require_torch
-class BertModelTest(CommonTestCases.CommonModelTester):
+class BertModelTest(ModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (
         (

tests/test_modeling_common.py

@@ -69,9 +69,8 @@ def _config_zero_init(config):
     return configs_no_init
 
 
-class CommonTestCases:
+@require_torch
-    @require_torch
+class ModelTesterMixin:
-    class CommonModelTester(unittest.TestCase):
 
     model_tester = None
     all_model_classes = ()
@@ -612,7 +611,8 @@ class CommonTestCases:
             with torch.no_grad():
                 outputs = model(**inputs_dict)
 
-    class GPTModelTester(CommonModelTester):
+
+class GPTModelTester(ModelTesterMixin):
     def __init__(
         self,
         parent,

tests/test_modeling_ctrl.py

@@ -13,10 +13,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import is_torch_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_common import CommonTestCases, ids_tensor
+from .test_modeling_common import ModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_torch, slow, torch_device
 
 
@@ -25,7 +27,7 @@ if is_torch_available():
 
 
 @require_torch
-class CTRLModelTest(CommonTestCases.CommonModelTester):
+class CTRLModelTest(ModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (CTRLModel, CTRLLMHeadModel) if is_torch_available() else ()
     test_pruning = False

tests/test_modeling_distilbert.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import is_torch_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_common import CommonTestCases, ids_tensor
+from .test_modeling_common import ModelTesterMixin, ids_tensor
 from .utils import require_torch, torch_device
 
 
@@ -33,7 +35,7 @@ if is_torch_available():
 
 
 @require_torch
-class DistilBertModelTest(CommonTestCases.CommonModelTester):
+class DistilBertModelTest(ModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (
         (DistilBertModel, DistilBertForMaskedLM, DistilBertForQuestionAnswering, DistilBertForSequenceClassification)

tests/test_modeling_gpt2.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import is_torch_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_common import CommonTestCases, ids_tensor
+from .test_modeling_common import ModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_torch, slow, torch_device
 
 
@@ -32,7 +34,7 @@ if is_torch_available():
 
 
 @require_torch
-class GPT2ModelTest(CommonTestCases.CommonModelTester):
+class GPT2ModelTest(ModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (GPT2Model, GPT2LMHeadModel, GPT2DoubleHeadsModel) if is_torch_available() else ()
 

tests/test_modeling_openai.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import is_torch_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_common import CommonTestCases, ids_tensor
+from .test_modeling_common import ModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_torch, slow, torch_device
 
 
@@ -32,7 +34,7 @@ if is_torch_available():
 
 
 @require_torch
-class OpenAIGPTModelTest(CommonTestCases.CommonModelTester):
+class OpenAIGPTModelTest(ModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (
         (OpenAIGPTModel, OpenAIGPTLMHeadModel, OpenAIGPTDoubleHeadsModel) if is_torch_available() else ()

tests/test_modeling_roberta.py

@@ -19,7 +19,7 @@ import unittest
 from transformers import is_torch_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_common import CommonTestCases, ids_tensor
+from .test_modeling_common import ModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_torch, slow, torch_device
 
 
@@ -37,7 +37,7 @@ if is_torch_available():
 
 
 @require_torch
-class RobertaModelTest(CommonTestCases.CommonModelTester):
+class RobertaModelTest(ModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (RobertaForMaskedLM, RobertaModel) if is_torch_available() else ()
 

tests/test_modeling_t5.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import is_torch_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_common import CommonTestCases, ids_tensor
+from .test_modeling_common import ModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_torch, slow
 
 
@@ -27,7 +29,7 @@ if is_torch_available():
 
 
 @require_torch
-class T5ModelTest(CommonTestCases.CommonModelTester):
+class T5ModelTest(ModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (T5Model, T5WithLMHeadModel) if is_torch_available() else ()
     test_pruning = False

tests/test_modeling_tf_albert.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import AlbertConfig, is_tf_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_tf_common import TFCommonTestCases, ids_tensor
+from .test_modeling_tf_common import TFModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_tf, slow
 
 
@@ -31,7 +33,7 @@ if is_tf_available():
 
 
 @require_tf
-class TFAlbertModelTest(TFCommonTestCases.TFCommonModelTester):
+class TFAlbertModelTest(TFModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (
         (TFAlbertModel, TFAlbertForMaskedLM, TFAlbertForSequenceClassification) if is_tf_available() else ()

tests/test_modeling_tf_bert.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import BertConfig, is_tf_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_tf_common import TFCommonTestCases, ids_tensor
+from .test_modeling_tf_common import TFModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_tf, slow
 
 
@@ -36,7 +38,7 @@ if is_tf_available():
 
 
 @require_tf
-class TFBertModelTest(TFCommonTestCases.TFCommonModelTester):
+class TFBertModelTest(TFModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (
         (

tests/test_modeling_tf_common.py

@@ -20,7 +20,6 @@ import random
 import shutil
 import sys
 import tempfile
-import unittest
 
 from transformers import is_tf_available, is_torch_available
 
@@ -59,9 +58,8 @@ def _config_zero_init(config):
     return configs_no_init
 
 
-class TFCommonTestCases:
+@require_tf
-    @require_tf
+class TFModelTesterMixin:
-    class TFCommonModelTester(unittest.TestCase):
 
     model_tester = None
     all_model_classes = ()
@@ -168,12 +166,8 @@ class TFCommonTestCases:
 
         if self.is_encoder_decoder:
             input_ids = {
-                    "decoder_input_ids": tf.keras.Input(
+                "decoder_input_ids": tf.keras.Input(batch_shape=(2, 2000), name="decoder_input_ids", dtype="int32"),
-                        batch_shape=(2, 2000), name="decoder_input_ids", dtype="int32"
+                "encoder_input_ids": tf.keras.Input(batch_shape=(2, 2000), name="encoder_input_ids", dtype="int32"),
-                    ),
-                    "encoder_input_ids": tf.keras.Input(
-                        batch_shape=(2, 2000), name="encoder_input_ids", dtype="int32"
-                    ),
             }
         else:
             input_ids = tf.keras.Input(batch_shape=(2, 2000), name="input_ids", dtype="int32")
@@ -209,9 +203,7 @@ class TFCommonTestCases:
             outputs_dict = model(inputs_dict)
 
             inputs_keywords = copy.deepcopy(inputs_dict)
-                input_ids = inputs_keywords.pop(
+            input_ids = inputs_keywords.pop("input_ids" if not self.is_encoder_decoder else "decoder_input_ids", None)
-                    "input_ids" if not self.is_encoder_decoder else "decoder_input_ids", None
-                )
             outputs_keywords = model(input_ids, **inputs_keywords)
 
             output_dict = outputs_dict[0].numpy()

tests/test_modeling_tf_ctrl.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import CTRLConfig, is_tf_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_tf_common import TFCommonTestCases, ids_tensor
+from .test_modeling_tf_common import TFModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_tf, slow
 
 
@@ -26,7 +28,7 @@ if is_tf_available():
 
 
 @require_tf
-class TFCTRLModelTest(TFCommonTestCases.TFCommonModelTester):
+class TFCTRLModelTest(TFModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (TFCTRLModel, TFCTRLLMHeadModel) if is_tf_available() else ()
 

tests/test_modeling_tf_distilbert.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import DistilBertConfig, is_tf_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_tf_common import TFCommonTestCases, ids_tensor
+from .test_modeling_tf_common import TFModelTesterMixin, ids_tensor
 from .utils import require_tf
 
 
@@ -31,7 +33,7 @@ if is_tf_available():
 
 
 @require_tf
-class TFDistilBertModelTest(TFCommonTestCases.TFCommonModelTester):
+class TFDistilBertModelTest(TFModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (
         (

tests/test_modeling_tf_gpt2.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import GPT2Config, is_tf_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_tf_common import TFCommonTestCases, ids_tensor
+from .test_modeling_tf_common import TFModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_tf, slow
 
 
@@ -32,7 +34,7 @@ if is_tf_available():
 
 
 @require_tf
-class TFGPT2ModelTest(TFCommonTestCases.TFCommonModelTester):
+class TFGPT2ModelTest(TFModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (TFGPT2Model, TFGPT2LMHeadModel, TFGPT2DoubleHeadsModel) if is_tf_available() else ()
     # all_model_classes = (TFGPT2Model, TFGPT2LMHeadModel) if is_tf_available() else ()

tests/test_modeling_tf_openai_gpt.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import OpenAIGPTConfig, is_tf_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_tf_common import TFCommonTestCases, ids_tensor
+from .test_modeling_tf_common import TFModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_tf, slow
 
 
@@ -32,7 +34,7 @@ if is_tf_available():
 
 
 @require_tf
-class TFOpenAIGPTModelTest(TFCommonTestCases.TFCommonModelTester):
+class TFOpenAIGPTModelTest(TFModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (
         (TFOpenAIGPTModel, TFOpenAIGPTLMHeadModel, TFOpenAIGPTDoubleHeadsModel) if is_tf_available() else ()

tests/test_modeling_tf_roberta.py

@@ -19,7 +19,7 @@ import unittest
 from transformers import RobertaConfig, is_tf_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_tf_common import TFCommonTestCases, ids_tensor
+from .test_modeling_tf_common import TFModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_tf, slow
 
 
@@ -36,7 +36,7 @@ if is_tf_available():
 
 
 @require_tf
-class TFRobertaModelTest(TFCommonTestCases.TFCommonModelTester):
+class TFRobertaModelTest(TFModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (
         (TFRobertaModel, TFRobertaForMaskedLM, TFRobertaForSequenceClassification) if is_tf_available() else ()

tests/test_modeling_tf_t5.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import T5Config, is_tf_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_tf_common import TFCommonTestCases, ids_tensor
+from .test_modeling_tf_common import TFModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_tf, slow
 
 
@@ -26,7 +28,7 @@ if is_tf_available():
 
 
 @require_tf
-class TFT5ModelTest(TFCommonTestCases.TFCommonModelTester):
+class TFT5ModelTest(TFModelTesterMixin, unittest.TestCase):
 
     is_encoder_decoder = True
     all_model_classes = (TFT5Model, TFT5WithLMHeadModel) if is_tf_available() else ()

tests/test_modeling_tf_transfo_xl.py

@@ -15,11 +15,12 @@
 from __future__ import absolute_import, division, print_function
 
 import random
+import unittest
 
 from transformers import TransfoXLConfig, is_tf_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_tf_common import TFCommonTestCases, ids_tensor
+from .test_modeling_tf_common import TFModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_tf, slow
 
 
@@ -33,7 +34,7 @@ if is_tf_available():
 
 
 @require_tf
-class TFTransfoXLModelTest(TFCommonTestCases.TFCommonModelTester):
+class TFTransfoXLModelTest(TFModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (TFTransfoXLModel, TFTransfoXLLMHeadModel) if is_tf_available() else ()
     test_pruning = False

tests/test_modeling_tf_xlm.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import is_tf_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_tf_common import TFCommonTestCases, ids_tensor
+from .test_modeling_tf_common import TFModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_tf, slow
 
 
@@ -34,7 +36,7 @@ if is_tf_available():
 
 
 @require_tf
-class TFXLMModelTest(TFCommonTestCases.TFCommonModelTester):
+class TFXLMModelTest(TFModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (
         (TFXLMModel, TFXLMWithLMHeadModel, TFXLMForSequenceClassification, TFXLMForQuestionAnsweringSimple)

tests/test_modeling_tf_xlnet.py

@@ -15,11 +15,12 @@
 from __future__ import absolute_import, division, print_function
 
 import random
+import unittest
 
 from transformers import XLNetConfig, is_tf_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_tf_common import TFCommonTestCases, ids_tensor
+from .test_modeling_tf_common import TFModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_tf, slow
 
 
@@ -37,7 +38,7 @@ if is_tf_available():
 
 
 @require_tf
-class TFXLNetModelTest(TFCommonTestCases.TFCommonModelTester):
+class TFXLNetModelTest(TFModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (
         (

tests/test_modeling_transfo_xl.py

@@ -15,11 +15,12 @@
 from __future__ import absolute_import, division, print_function
 
 import random
+import unittest
 
 from transformers import is_torch_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_common import CommonTestCases, ids_tensor
+from .test_modeling_common import ModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_torch, slow, torch_device
 
 
@@ -30,7 +31,7 @@ if is_torch_available():
 
 
 @require_torch
-class TransfoXLModelTest(CommonTestCases.CommonModelTester):
+class TransfoXLModelTest(ModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (TransfoXLModel, TransfoXLLMHeadModel) if is_torch_available() else ()
     test_pruning = False

tests/test_modeling_xlm.py

@@ -14,10 +14,12 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
+import unittest
+
 from transformers import is_torch_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_common import CommonTestCases, ids_tensor
+from .test_modeling_common import ModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_torch, slow, torch_device
 
 
@@ -34,7 +36,7 @@ if is_torch_available():
 
 
 @require_torch
-class XLMModelTest(CommonTestCases.CommonModelTester):
+class XLMModelTest(ModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (
         (

tests/test_modeling_xlnet.py

@@ -15,11 +15,12 @@
 from __future__ import absolute_import, division, print_function
 
 import random
+import unittest
 
 from transformers import is_torch_available
 
 from .test_configuration_common import ConfigTester
-from .test_modeling_common import CommonTestCases, ids_tensor
+from .test_modeling_common import ModelTesterMixin, ids_tensor
 from .utils import CACHE_DIR, require_torch, slow, torch_device
 
 
@@ -38,7 +39,7 @@ if is_torch_available():
 
 
 @require_torch
-class XLNetModelTest(CommonTestCases.CommonModelTester):
+class XLNetModelTest(ModelTesterMixin, unittest.TestCase):
 
     all_model_classes = (
         (