assertEquals("zh", languageHelper.getSupportedLanguage("zh"));
        assertEquals("ko", languageHelper.getSupportedLanguage("ko"));
    }

    @Test
    public void test_getSupportedLanguage_unsupported() {
        assertNull(languageHelper.getSupportedLanguage("fr"));
        assertNull(languageHelper.getSupportedLanguage("de"));
        assertNull(languageHelper.getSupportedLanguage("unknown"));
    }