add a template to add missing tokenization test (#16553)

* add a template to add missing tokenization test

* add cookiecutter setting

* improve doc

* Update templates/adding_a_missing_tokenization_test/README.md
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>

templates/adding_a_missing_tokenization_test/README.md

+<!---
+Copyright 2022 The HuggingFace Team. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+
+This folder contains a template to add a tokenization test. 
+
+## Usage
+
+Using the `cookiecutter` utility requires to have all the `dev` dependencies installed. 
+
+Let's first [fork](https://docs.github.com/en/get-started/quickstart/fork-a-repo) the `transformers` repo on github. Once it's done you can clone your fork and install `transformers` in our environment:
+
+```shell script
+git clone https://github.com/YOUR-USERNAME/transformers
+cd transformers
+pip install -e ".[dev]"
+```
+
+Once the installation is done, you can generate the template by running the following command. Be careful, the template will be generated inside a new folder in your current working directory.
+
+```shell script
+cookiecutter path-to-the folder/adding_a_missing_tokenization_test/
+```
+
+You will then have to answer some questions about the tokenizer for which you want to add tests. The `modelname` should be cased according to the plain text casing, i.e., BERT, RoBERTa, DeBERTa.
+
+Once the command has finished, you should have a one new file inside the newly created folder named `test_tokenization_Xxx.py`. At this point the template is finished and you can move it to the sub-folder of the corresponding model in the test folder.

templates/adding_a_missing_tokenization_test/cookiecutter-template-{{cookiecutter.modelname}}/test_tokenization_{{cookiecutter.lowercase_modelname}}.py

+# coding=utf-8
+# Copyright 2022 {{cookiecutter.authors}}. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+""" Testing suite for the {{cookiecutter.modelname}} tokenizer. """
+
+
+import unittest
+
+{% if cookiecutter.has_slow_class == "True" and  cookiecutter.has_fast_class == "True" -%}
+from transformers import {{cookiecutter.camelcase_modelname}}Tokenizer, {{cookiecutter.camelcase_modelname}}TokenizerFast
+{% elif  cookiecutter.has_slow_class == "True" -%}
+from transformers import {{cookiecutter.camelcase_modelname}}Tokenizer
+{% elif  cookiecutter.has_fast_class == "True" -%}
+from transformers import {{cookiecutter.camelcase_modelname}}TokenizerFast
+{% endif -%}
+{% if cookiecutter.has_fast_class == "True" and  cookiecutter.slow_tokenizer_use_sentencepiece == "True" -%}
+from transformers.testing_utils import require_sentencepiece, require_tokenizers
+from ..test_tokenization_common import TokenizerTesterMixin
+
+
+@require_sentencepiece
+@require_tokenizers
+{% elif  cookiecutter.slow_tokenizer_use_sentencepiece == "True" -%}
+from transformers.testing_utils import require_sentencepiece
+from ..test_tokenization_common import TokenizerTesterMixin
+
+
+@require_sentencepiece
+{% elif  cookiecutter.has_fast_class == "True" -%}
+from transformers.testing_utils import require_tokenizers
+from ..test_tokenization_common import TokenizerTesterMixin
+
+
+@require_tokenizers
+{% else -%}
+from ..test_tokenization_common import TokenizerTesterMixin
+
+
+{% endif -%}
+class {{cookiecutter.camelcase_modelname}}TokenizationTest(TokenizerTesterMixin, unittest.TestCase):
+    {% if cookiecutter.has_slow_class == "True" -%}
+    tokenizer_class = {{cookiecutter.camelcase_modelname}}Tokenizer
+    test_slow_tokenizer = True
+    {% else -%}
+    tokenizer_class = None
+    test_slow_tokenizer = False
+    {% endif -%}
+    {% if cookiecutter.has_fast_class == "True" -%}
+    rust_tokenizer_class = {{cookiecutter.camelcase_modelname}}TokenizerFast
+    test_rust_tokenizer = True
+    {% else -%}
+    rust_tokenizer_class = None
+    test_rust_tokenizer = False
+    {% endif -%}
+    {% if  cookiecutter.slow_tokenizer_use_sentencepiece == "True" -%}
+    test_sentencepiece = True
+    {% endif -%}
+    # TODO: Check in `TokenizerTesterMixin` if other attributes need to be changed
+    def setUp(self):
+        super().setUp()
+
+        raise NotImplementedError(
+            "Here you have to implement the saving of a toy tokenizer in "
+            "`self.tmpdirname`."
+        )
+
+    # TODO: add tests with hard-coded target values 
\ No newline at end of file

templates/adding_a_missing_tokenization_test/cookiecutter.json

+{
+  "modelname": "BrandNewBERT",
+  "uppercase_modelname": "BRAND_NEW_BERT",
+  "lowercase_modelname": "brand_new_bert",
+  "camelcase_modelname": "BrandNewBert",
+  "has_slow_class": ["True", "False"],
+  "has_fast_class": ["True", "False"],
+  "slow_tokenizer_use_sentencepiece": ["True", "False"],
+  "authors": "The HuggingFace Team"
+}