assertNull(languageHelper.getSupportedLanguage("de"));
        assertNull(languageHelper.getSupportedLanguage("unknown"));
    }

    @Test
    public void test_getSupportedLanguage_blank() {
        assertNull(languageHelper.getSupportedLanguage(null));
        assertNull(languageHelper.getSupportedLanguage(""));
        assertNull(languageHelper.getSupportedLanguage("   "));
    }