Auto feature extractor (#11097)

* AutoFeatureExtractor

* Init and first tests

* Tests

* Damn you gitignore

* Quality

* Defensive test for when not all backends are here

* Use pattern for Speech2Text models

tests/test_feature_extraction_speech_to_text.py

@@ -20,12 +20,15 @@ import unittest
 
 import numpy as np
 
-from transformers import Speech2TextFeatureExtractor
+from transformers import is_speech_available
 from transformers.testing_utils import require_torch, require_torchaudio
 
 from .test_sequence_feature_extraction_common import SequenceFeatureExtractionTestMixin
 
 
+if is_speech_available():
+    from transformers import Speech2TextFeatureExtractor
+
 global_rng = random.Random()
 
 
@@ -101,7 +104,7 @@ class Speech2TextFeatureExtractionTester(unittest.TestCase):
 @require_torchaudio
 class Speech2TextFeatureExtractionTest(SequenceFeatureExtractionTestMixin, unittest.TestCase):
 
-    feature_extraction_class = Speech2TextFeatureExtractor
+    feature_extraction_class = Speech2TextFeatureExtractor if is_speech_available() else None
 
     def setUp(self):
         self.feat_extract_tester = Speech2TextFeatureExtractionTester(self)