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Testing Multi-Language Phonemization Systems in Coqui-AI TTS

This test suite validates the functionality of various text phonemization implementations in the Coqui-AI TTS library. It tests multiple phonemizers including ESpeak, Gruut, and language-specific phonemizers for Japanese, Chinese, and Bangla, ensuring accurate conversion of text to phonetic representations.

Test Coverage Overview

The test suite provides comprehensive coverage of phonemization capabilities across multiple languages and backends.

Tests ESpeak phonemizer with different versions and backends
Validates Gruut phonemizer with stress patterns and phoneme conversion
Covers language-specific phonemizers (Japanese, Chinese, Bangla)
Tests edge cases including punctuation handling and version compatibility

Implementation Analysis

The testing approach uses unittest framework with systematic validation of phoneme outputs.

Key patterns include:

Version-specific test cases for ESpeak compatibility
Consistent verification of phoneme patterns across languages
Standardized interface testing for all phonemizer implementations

Technical Details

Testing infrastructure includes:

Python unittest framework
ESpeak and ESpeak-NG backends
Version comparison using packaging.version
Custom phonemizer implementations for specific languages
MultiPhonemizer for handling multiple language support

Best Practices Demonstrated

The test suite exemplifies high-quality testing practices:

Comprehensive setUp methods for test initialization
Consistent interface testing across implementations
Thorough version compatibility checks
Clear test case organization by phonemizer type
Robust error handling and edge case coverage

coqui-ai/tts

tests/text_tests/test_phonemizer.py

            
import unittest

from packaging.version import Version

from TTS.tts.utils.text.phonemizers import ESpeak, Gruut, JA_JP_Phonemizer, ZH_CN_Phonemizer
from TTS.tts.utils.text.phonemizers.bangla_phonemizer import BN_Phonemizer
from TTS.tts.utils.text.phonemizers.multi_phonemizer import MultiPhonemizer

EXAMPLE_TEXTs = [
    "Recent research at Harvard has shown meditating",
    "for as little as 8 weeks can actually increase, the grey matter",
    "in the parts of the brain responsible",
    "for emotional regulation and learning!",
]


EXPECTED_ESPEAK_PHONEMES = [
    "ɹ|ˈiː|s|ə|n|t ɹ|ɪ|s|ˈɜː|tʃ æ|t h|ˈɑːɹ|v|ɚ|d h|ɐ|z ʃ|ˈoʊ|n m|ˈɛ|d|ɪ|t|ˌeɪ|ɾ|ɪ|ŋ",
    "f|ɔː|ɹ æ|z l|ˈɪ|ɾ|əl æ|z ˈeɪ|t w|ˈiː|k|s k|æ|n ˈæ|k|tʃ|uː|əl|i| ˈɪ|n|k|ɹ|iː|s, ð|ə ɡ|ɹ|ˈeɪ m|ˈæ|ɾ|ɚ",
    "ɪ|n|ð|ə p|ˈɑːɹ|t|s ʌ|v|ð|ə b|ɹ|ˈeɪ|n ɹ|ɪ|s|p|ˈɑː|n|s|ə|b|əl",
    "f|ɔː|ɹ ɪ|m|ˈoʊ|ʃ|ə|n|əl ɹ|ˌɛ|ɡ|j|uː|l|ˈeɪ|ʃ|ə|n|| æ|n|d l|ˈɜː|n|ɪ|ŋ!",
]


EXPECTED_ESPEAK_v1_48_15_PHONEMES = [
    "ɹ|ˈiː|s|ə|n|t ɹ|ɪ|s|ˈɜː|tʃ æ|t h|ˈɑːɹ|v|ɚ|d h|ɐ|z ʃ|ˈoʊ|n m|ˈɛ|d|ᵻ|t|ˌeɪ|ɾ|ɪ|ŋ",
    "f|ɔː|ɹ æ|z l|ˈɪ|ɾ|əl æ|z ˈeɪ|t w|ˈiː|k|s k|æ|n ˈæ|k|tʃ|uː|əl|i| ˈɪ|n|k|ɹ|iː|s, ð|ə ɡ|ɹ|ˈeɪ m|ˈæ|ɾ|ɚ",
    "ɪ|n|ð|ə p|ˈɑːɹ|t|s ʌ|v|ð|ə b|ɹ|ˈeɪ|n ɹ|ɪ|s|p|ˈɑː|n|s|ə|b|əl",
    "f|ɔː|ɹ ɪ|m|ˈoʊ|ʃ|ə|n|əl ɹ|ˌɛ|ɡ|j|uː|l|ˈeɪ|ʃ|ə|n|| æ|n|d l|ˈɜː|n|ɪ|ŋ!",
]


EXPECTED_ESPEAKNG_PHONEMES = [
    "ɹ|ˈiː|s|ə|n|t ɹ|ᵻ|s|ˈɜː|tʃ æ|t h|ˈɑːɹ|v|ɚ|d h|ɐ|z ʃ|ˈoʊ|n m|ˈɛ|d|ᵻ|t|ˌeɪ|ɾ|ɪ|ŋ",
    "f|ɔː|ɹ æ|z l|ˈɪ|ɾ|əl æ|z ˈeɪ|t w|ˈiː|k|s k|æ|n ˈæ|k|tʃ|uː|əl|i| ˈɪ|ŋ|k|ɹ|iː|s, ð|ə ɡ|ɹ|ˈeɪ m|ˈæ|ɾ|ɚ",
    "ɪ|n|ð|ə p|ˈɑːɹ|t|s ʌ|v|ð|ə b|ɹ|ˈeɪ|n ɹ|ᵻ|s|p|ˈɑː|n|s|ᵻ|b|əl",
    "f|ɔː|ɹ ɪ|m|ˈoʊ|ʃ|ə|n|əl ɹ|ˌɛ|ɡ|j|ʊ|l|ˈeɪ|ʃ|ə|n|| æ|n|d l|ˈɜː|n|ɪ|ŋ!",
]


class TestEspeakPhonemizer(unittest.TestCase):
    def setUp(self):
        self.phonemizer = ESpeak(language="en-us", backend="espeak")

        if Version(self.phonemizer.backend_version) >= Version("1.48.15"):
            target_phonemes = EXPECTED_ESPEAK_v1_48_15_PHONEMES
        else:
            target_phonemes = EXPECTED_ESPEAK_PHONEMES

        for text, ph in zip(EXAMPLE_TEXTs, target_phonemes):
            phonemes = self.phonemizer.phonemize(text)
            self.assertEqual(phonemes, ph)

        # multiple punctuations
        text = "Be a voice, not an! echo?"
        gt = "biː ɐ vˈɔɪs, nˈɑːt ɐn! ˈɛkoʊ?"
        if Version(self.phonemizer.backend_version) >= Version("1.48.15"):
            gt = "biː ɐ vˈɔɪs, nˈɑːt æn! ˈɛkoʊ?"
        output = self.phonemizer.phonemize(text, separator="|")
        output = output.replace("|", "")
        self.assertEqual(output, gt)

        # not ending with punctuation
        text = "Be a voice, not an! echo"
        gt = "biː ɐ vˈɔɪs, nˈɑːt ɐn! ˈɛkoʊ"
        if Version(self.phonemizer.backend_version) >= Version("1.48.15"):
            gt = "biː ɐ vˈɔɪs, nˈɑːt æn! ˈɛkoʊ"
        output = self.phonemizer.phonemize(text, separator="")
        self.assertEqual(output, gt)

        # extra space after the sentence
        text = "Be a voice, not an! echo.  "
        gt = "biː ɐ vˈɔɪs, nˈɑːt ɐn! ˈɛkoʊ."
        if Version(self.phonemizer.backend_version) >= Version("1.48.15"):
            gt = "biː ɐ vˈɔɪs, nˈɑːt æn! ˈɛkoʊ."
        output = self.phonemizer.phonemize(text, separator="")
        self.assertEqual(output, gt)

    def test_name(self):
        self.assertEqual(self.phonemizer.name(), "espeak")

    def test_get_supported_languages(self):
        self.assertIsInstance(self.phonemizer.supported_languages(), dict)

    def test_get_version(self):
        self.assertIsInstance(self.phonemizer.version(), str)

    def test_is_available(self):
        self.assertTrue(self.phonemizer.is_available())


class TestEspeakNgPhonemizer(unittest.TestCase):
    def setUp(self):
        self.phonemizer = ESpeak(language="en-us", backend="espeak-ng")

        for text, ph in zip(EXAMPLE_TEXTs, EXPECTED_ESPEAKNG_PHONEMES):
            phonemes = self.phonemizer.phonemize(text)
            self.assertEqual(phonemes, ph)

        # multiple punctuations
        text = "Be a voice, not an! echo?"
        gt = "biː ɐ vˈɔɪs, nˈɑːt æn! ˈɛkoʊ?"
        output = self.phonemizer.phonemize(text, separator="|")
        output = output.replace("|", "")
        self.assertEqual(output, gt)

        # not ending with punctuation
        text = "Be a voice, not an! echo"
        gt = "biː ɐ vˈɔɪs, nˈɑːt æn! ˈɛkoʊ"
        output = self.phonemizer.phonemize(text, separator="")
        self.assertEqual(output, gt)

        # extra space after the sentence
        text = "Be a voice, not an! echo.  "
        gt = "biː ɐ vˈɔɪs, nˈɑːt æn! ˈɛkoʊ."
        output = self.phonemizer.phonemize(text, separator="")
        self.assertEqual(output, gt)

    def test_name(self):
        self.assertEqual(self.phonemizer.name(), "espeak")

    def test_get_supported_languages(self):
        self.assertIsInstance(self.phonemizer.supported_languages(), dict)

    def test_get_version(self):
        self.assertIsInstance(self.phonemizer.version(), str)

    def test_is_available(self):
        self.assertTrue(self.phonemizer.is_available())


class TestGruutPhonemizer(unittest.TestCase):
    def setUp(self):
        self.phonemizer = Gruut(language="en-us", use_espeak_phonemes=True, keep_stress=False)
        self.EXPECTED_PHONEMES = [
            "ɹ|i|ː|s|ə|n|t| ɹ|ᵻ|s|ɜ|ː|t|ʃ| æ|ɾ| h|ɑ|ː|ɹ|v|ɚ|d| h|ɐ|z| ʃ|o|ʊ|n| m|ɛ|d|ᵻ|t|e|ɪ|ɾ|ɪ|ŋ",
            "f|ɔ|ː|ɹ| æ|z| l|ɪ|ɾ|ə|l| æ|z| e|ɪ|t| w|i|ː|k|s| k|æ|ŋ| æ|k|t|ʃ|u|ː|ə|l|i| ɪ|ŋ|k|ɹ|i|ː|s, ð|ə| ɡ|ɹ|e|ɪ| m|æ|ɾ|ɚ",
            "ɪ|n| ð|ə| p|ɑ|ː|ɹ|t|s| ʌ|v| ð|ə| b|ɹ|e|ɪ|n| ɹ|ᵻ|s|p|ɑ|ː|n|s|ᵻ|b|ə|l",
            "f|ɔ|ː|ɹ| ɪ|m|o|ʊ|ʃ|ə|n|ə|l| ɹ|ɛ|ɡ|j|ʊ|l|e|ɪ|ʃ|ə|n| æ|n|d| l|ɜ|ː|n|ɪ|ŋ!",
        ]

    def test_phonemize(self):
        for text, ph in zip(EXAMPLE_TEXTs, self.EXPECTED_PHONEMES):
            phonemes = self.phonemizer.phonemize(text, separator="|")
            self.assertEqual(phonemes, ph)

        # multiple punctuations
        text = "Be a voice, not an! echo?"
        gt = "biː ɐ vɔɪs, nɑːt ɐn! ɛkoʊ?"
        output = self.phonemizer.phonemize(text, separator="|")
        output = output.replace("|", "")
        self.assertEqual(output, gt)

        # not ending with punctuation
        text = "Be a voice, not an! echo"
        gt = "biː ɐ vɔɪs, nɑːt ɐn! ɛkoʊ"
        output = self.phonemizer.phonemize(text, separator="")
        self.assertEqual(output, gt)

        # extra space after the sentence
        text = "Be a voice, not an! echo.  "
        gt = "biː ɐ vɔɪs, nɑːt ɐn! ɛkoʊ."
        output = self.phonemizer.phonemize(text, separator="")
        self.assertEqual(output, gt)

    def test_name(self):
        self.assertEqual(self.phonemizer.name(), "gruut")

    def test_get_supported_languages(self):
        self.assertIsInstance(self.phonemizer.supported_languages(), list)

    def test_get_version(self):
        self.assertIsInstance(self.phonemizer.version(), str)

    def test_is_available(self):
        self.assertTrue(self.phonemizer.is_available())


class TestJA_JPPhonemizer(unittest.TestCase):
    def setUp(self):
        self.phonemizer = JA_JP_Phonemizer()
        self._TEST_CASES = """
            どちらに行きますか？/dochiraniikimasuka?
            今日は温泉に、行きます。/kyo:waoNseNni,ikimasu.
            「A」から「Z」までです。/e:karazeqtomadedesu.
            そうですね！/so:desune!
            クジラは哺乳類です。/kujirawahonyu:ruidesu.
            ヴィディオを見ます。/bidioomimasu.
            今日は８月22日です/kyo:wahachigatsuniju:ninichidesu
            xyzとαβγ/eqkusuwaizeqtotoarufabe:tagaNma
            値段は$12.34です/nedaNwaju:niteNsaNyoNdorudesu
            """

    def test_phonemize(self):
        for line in self._TEST_CASES.strip().split("
"):
            text, phone = line.split("/")
            self.assertEqual(self.phonemizer.phonemize(text, separator=""), phone)

    def test_name(self):
        self.assertEqual(self.phonemizer.name(), "ja_jp_phonemizer")

    def test_get_supported_languages(self):
        self.assertIsInstance(self.phonemizer.supported_languages(), dict)

    def test_get_version(self):
        self.assertIsInstance(self.phonemizer.version(), str)

    def test_is_available(self):
        self.assertTrue(self.phonemizer.is_available())


class TestZH_CN_Phonemizer(unittest.TestCase):
    def setUp(self):
        self.phonemizer = ZH_CN_Phonemizer()
        self._TEST_CASES = ""

    def test_phonemize(self):
        # TODO: implement ZH phonemizer tests
        pass

    def test_name(self):
        self.assertEqual(self.phonemizer.name(), "zh_cn_phonemizer")

    def test_get_supported_languages(self):
        self.assertIsInstance(self.phonemizer.supported_languages(), dict)

    def test_get_version(self):
        self.assertIsInstance(self.phonemizer.version(), str)

    def test_is_available(self):
        self.assertTrue(self.phonemizer.is_available())


class TestBN_Phonemizer(unittest.TestCase):
    def setUp(self):
        self.phonemizer = BN_Phonemizer()
        self._TEST_CASES = "রাসূলুল্লাহ সাল্লাল্লাহু আলাইহি ওয়া সাল্লাম শিক্ষা দিয়েছেন যে, কেউ যদি কোন খারাপ কিছুর সম্মুখীন হয়, তখনও যেন"
        self._EXPECTED = "রাসূলুল্লাহ সাল্লাল্লাহু আলাইহি ওয়া সাল্লাম শিক্ষা দিয়েছেন যে কেউ যদি কোন খারাপ কিছুর সম্মুখীন হয় তখনও যেন।"

    def test_phonemize(self):
        self.assertEqual(self.phonemizer.phonemize(self._TEST_CASES, separator=""), self._EXPECTED)

    def test_name(self):
        self.assertEqual(self.phonemizer.name(), "bn_phonemizer")

    def test_get_supported_languages(self):
        self.assertIsInstance(self.phonemizer.supported_languages(), dict)

    def test_get_version(self):
        self.assertIsInstance(self.phonemizer.version(), str)

    def test_is_available(self):
        self.assertTrue(self.phonemizer.is_available())


class TestMultiPhonemizer(unittest.TestCase):
    def setUp(self):
        self.phonemizer = MultiPhonemizer({"tr": "espeak", "en-us": "", "de": "gruut", "zh-cn": ""})

    def test_phonemize(self):
        # Enlish espeak
        text = "Be a voice, not an! echo?"
        gt = "biː ɐ vˈɔɪs, nˈɑːt æn! ˈɛkoʊ?"
        output = self.phonemizer.phonemize(text, separator="|", language="en-us")
        output = output.replace("|", "")
        self.assertEqual(output, gt)

        # German gruut
        text = "Hallo, das ist ein Deutches Beipiel!"
        gt = "haloː, das ɪst aeːn dɔɔʏ̯tçəs bəʔiːpiːl!"
        output = self.phonemizer.phonemize(text, separator="|", language="de")
        output = output.replace("|", "")
        self.assertEqual(output, gt)

    def test_phonemizer_initialization(self):
        # test with unsupported language
        with self.assertRaises(ValueError):
            MultiPhonemizer({"tr": "espeak", "xx": ""})

        # test with unsupported phonemizer
        with self.assertRaises(ValueError):
            MultiPhonemizer({"tr": "espeak", "fr": "xx"})

    def test_sub_phonemizers(self):
        for lang in self.phonemizer.lang_to_phonemizer_name.keys():
            self.assertEqual(lang, self.phonemizer.lang_to_phonemizer[lang].language)
            self.assertEqual(
                self.phonemizer.lang_to_phonemizer_name[lang], self.phonemizer.lang_to_phonemizer[lang].name()
            )

    def test_name(self):
        self.assertEqual(self.phonemizer.name(), "multi-phonemizer")

    def test_get_supported_languages(self):
        self.assertIsInstance(self.phonemizer.supported_languages(), list)