fix tokenizer_class_from_name for models with - in the name (#13251)

* fix tokenizer_class_from_name

* Update src/transformers/models/auto/tokenization_auto.py

Co-authored-by: Lysandre Debut <lysandre@huggingface.co>

* add test

Co-authored-by: Lysandre Debut <lysandre@huggingface.co>

tests/test_tokenization_auto.py

@@ -29,7 +29,11 @@ from transformers import (
     RobertaTokenizerFast,
 )
 from transformers.models.auto.configuration_auto import AutoConfig
-from transformers.models.auto.tokenization_auto import TOKENIZER_MAPPING, get_tokenizer_config
+from transformers.models.auto.tokenization_auto import (
+    TOKENIZER_MAPPING,
+    get_tokenizer_config,
+    tokenizer_class_from_name,
+)
 from transformers.models.roberta.configuration_roberta import RobertaConfig
 from transformers.testing_utils import (
     DUMMY_DIFF_TOKENIZER_IDENTIFIER,
@@ -105,6 +109,24 @@ class AutoTokenizerTest(unittest.TestCase):
                     with self.subTest(msg=f"Testing if {child_config.__name__} is child of {parent_config.__name__}"):
                         self.assertFalse(issubclass(child_config, parent_config))
 
+    def test_model_name_edge_cases_in_mappings(self):
+        # tests: https://github.com/huggingface/transformers/pull/13251
+        # 1. models with `-`, e.g. xlm-roberta -> xlm_roberta
+        # 2. models that don't remap 1-1 from model-name to model file, e.g., openai-gpt -> openai
+        tokenizers = TOKENIZER_MAPPING.values()
+        tokenizer_names = []
+
+        for slow_tok, fast_tok in tokenizers:
+            if slow_tok is not None:
+                tokenizer_names.append(slow_tok.__name__)
+
+            if fast_tok is not None:
+                tokenizer_names.append(fast_tok.__name__)
+
+        for tokenizer_name in tokenizer_names:
+            # must find the right class
+            tokenizer_class_from_name(tokenizer_name)
+
     @require_tokenizers
     def test_from_pretrained_use_fast_toggle(self):
         self.assertIsInstance(AutoTokenizer.from_pretrained("bert-base-cased", use_fast=False), BertTokenizer)