Moving feature-extraction pipeline to new testing scheme (#12843)

* Update feature extraction pipelilne.

* Leaving 1 small model for actual values check.

* Fixes tests

- Better support for tokenizer with no pad token
- Increasing PegasusModelTesterConfig for pipelines
- Test of feature extraction are more permissive + don't test Multimodel
models + encoder-decoder.

* Fixing model loading with incorrect shape (+ model with HEAD).

* Update tests/test_pipelines_common.py

Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>

* Revert modeling_utils modification.

* Some corrections.

* Update tests/test_pipelines_common.py

Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>

* Update tests/test_pipelines_feature_extraction.py

Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>

* Syntax.

* Fixing text-classification tests.

* Don't modify this file.

Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>

tests/test_pipelines_text_classification.py

@@ -30,6 +30,24 @@ class TextClassificationPipelineTests(unittest.TestCase, metaclass=PipelineTestC
     model_mapping = MODEL_FOR_SEQUENCE_CLASSIFICATION_MAPPING
     tf_model_mapping = TF_MODEL_FOR_SEQUENCE_CLASSIFICATION_MAPPING
 
+    @require_torch
+    def test_pt_bert_small(self):
+        text_classifier = pipeline(
+            task="text-classification", model="Narsil/tiny-distilbert-sequence-classification", framework="pt"
+        )
+
+        outputs = text_classifier("This is great !")
+        self.assertEqual(nested_simplify(outputs), [{"label": "LABEL_1", "score": 0.502}])
+
+    @require_tf
+    def test_tf_bert_small(self):
+        text_classifier = pipeline(
+            task="text-classification", model="Narsil/tiny-distilbert-sequence-classification", framework="tf"
+        )
+
+        outputs = text_classifier("This is great !")
+        self.assertEqual(nested_simplify(outputs), [{"label": "LABEL_1", "score": 0.502}])
+
     @slow
     @require_torch
     def test_pt_bert(self):