transformers/tests/test_tokenization_roberta.py

# coding=utf-8
# Copyright 2018 The Google AI Language Team Authors.
#
# 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.


import json
import os
import unittest

from transformers.tokenization_roberta import VOCAB_FILES_NAMES, RobertaTokenizer

from .test_tokenization_common import TokenizerTesterMixin
from .utils import slow


class RobertaTokenizationTest(TokenizerTesterMixin, unittest.TestCase):
    tokenizer_class = RobertaTokenizer

    def setUp(self):
        super().setUp()

        # Adapted from Sennrich et al. 2015 and https://github.com/rsennrich/subword-nmt
        vocab = [
            "l",
            "o",
            "w",
            "e",
            "r",
            "s",
            "t",
            "i",
            "d",
            "n",
            "\u0120",
            "\u0120l",
            "\u0120n",
            "\u0120lo",
            "\u0120low",
            "er",
            "\u0120lowest",
            "\u0120newer",
            "\u0120wider",
            "<unk>",
        ]
        vocab_tokens = dict(zip(vocab, range(len(vocab))))
        merges = ["#version: 0.2", "\u0120 l", "\u0120l o", "\u0120lo w", "e r", ""]
        self.special_tokens_map = {"unk_token": "<unk>"}

        self.vocab_file = os.path.join(self.tmpdirname, VOCAB_FILES_NAMES["vocab_file"])
        self.merges_file = os.path.join(self.tmpdirname, VOCAB_FILES_NAMES["merges_file"])
        with open(self.vocab_file, "w", encoding="utf-8") as fp:
            fp.write(json.dumps(vocab_tokens) + "\n")
        with open(self.merges_file, "w", encoding="utf-8") as fp:
            fp.write("\n".join(merges))

    def get_tokenizer(self, **kwargs):
        kwargs.update(self.special_tokens_map)
        return RobertaTokenizer.from_pretrained(self.tmpdirname, **kwargs)

    def get_input_output_texts(self):
        input_text = "lower newer"
        output_text = "lower newer"
        return input_text, output_text

    def test_full_tokenizer(self):
        tokenizer = RobertaTokenizer(self.vocab_file, self.merges_file, **self.special_tokens_map)
        text = "lower newer"
        bpe_tokens = ["\u0120low", "er", "\u0120", "n", "e", "w", "er"]
        tokens = tokenizer.tokenize(text, add_prefix_space=True)
        self.assertListEqual(tokens, bpe_tokens)

        input_tokens = tokens + [tokenizer.unk_token]
        input_bpe_tokens = [14, 15, 10, 9, 3, 2, 15, 19]
        self.assertListEqual(tokenizer.convert_tokens_to_ids(input_tokens), input_bpe_tokens)

    def roberta_dict_integration_testing(self):
        tokenizer = self.get_tokenizer()

        self.assertListEqual(tokenizer.encode("Hello world!", add_special_tokens=False), [0, 31414, 232, 328, 2])
        self.assertListEqual(
            tokenizer.encode("Hello world! cécé herlolip 418", add_special_tokens=False),
            [0, 31414, 232, 328, 740, 1140, 12695, 69, 46078, 1588, 2],
        )

    @slow
    def test_sequence_builders(self):
        tokenizer = RobertaTokenizer.from_pretrained("roberta-base")

        text = tokenizer.encode("sequence builders", add_special_tokens=False)
        text_2 = tokenizer.encode("multi-sequence build", add_special_tokens=False)

        encoded_text_from_decode = tokenizer.encode("sequence builders", add_special_tokens=True)
        encoded_pair_from_decode = tokenizer.encode(
            "sequence builders", "multi-sequence build", add_special_tokens=True
        )

        encoded_sentence = tokenizer.build_inputs_with_special_tokens(text)
        encoded_pair = tokenizer.build_inputs_with_special_tokens(text, text_2)

        assert encoded_sentence == encoded_text_from_decode
        assert encoded_pair == encoded_pair_from_decode

    def test_space_encoding(self):
        tokenizer = self.get_tokenizer()

        sequence = "Encode this sequence."
        space_encoding = tokenizer.byte_encoder[" ".encode("utf-8")[0]]

        # Testing encoder arguments
        encoded = tokenizer.encode(sequence, add_special_tokens=False)
        first_char = tokenizer.convert_ids_to_tokens(encoded[0])[0]
        self.assertNotEqual(first_char, space_encoding)

        encoded = tokenizer.encode(sequence, add_special_tokens=False, add_prefix_space=True)
        first_char = tokenizer.convert_ids_to_tokens(encoded[0])[0]
        self.assertEqual(first_char, space_encoding)

        tokenizer.add_special_tokens({"bos_token": "<s>"})
        encoded = tokenizer.encode(sequence, add_special_tokens=True)
        first_char = tokenizer.convert_ids_to_tokens(encoded[1])[0]
        self.assertEqual(first_char, space_encoding)

        # Testing spaces after special tokenss
        mask = "<mask>"
        tokenizer.add_special_tokens({"mask_token": mask})
        mask_ind = tokenizer.convert_tokens_to_ids(mask)

        sequence = "Encode <mask> sequence"
        sequence_nospace = "Encode <mask>sequence"

        encoded = tokenizer.encode(sequence)
        mask_loc = encoded.index(mask_ind)
        first_char = tokenizer.convert_ids_to_tokens(encoded[mask_loc + 1])[0]
        self.assertEqual(first_char, space_encoding)

        encoded = tokenizer.encode(sequence_nospace)
        mask_loc = encoded.index(mask_ind)
        first_char = tokenizer.convert_ids_to_tokens(encoded[mask_loc + 1])[0]
        self.assertNotEqual(first_char, space_encoding)