JpnForPhp\Tests\Helper\HelperTest::testConvertKatakanaToHiraganaWhenMixCharacters PHP Method

    public function testConvertKatakanaToHiraganaWhenMixCharacters()
    {
        $result = Helper::convertKatakanaToHiragana($this->mixCharacters);
        $this->assertEquals('今日、Joo「じょお」は学校にいます。', $result);
    }