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

    public void test_getSupportedLanguage_unsupported() {
        assertNull(languageHelper.getSupportedLanguage("fr"));