static String getConfigValueAsString(ServiceConfiguration conf,
                                                String configProp) throws IllegalArgumentException {
        String value = getConfigValueAsStringImpl(conf, configProp);
        log.info("Configuration for [{}] is [{}]", configProp, value);
        return value;
    }
@Test
    public void testGetConfigValueAsStringReturnsNullIfMissing() {
        Properties props = new Properties();
        ServiceConfiguration config = new ServiceConfiguration();
        config.setProperties(props);
        String actual = ConfigUtils.getConfigValueAsString(config, "prop1");
        assertNull(actual);
    }