@Test(expected = IllegalStateException.class)
public void testDuplicateId() {

    // prepare properties
    Properties props = new Properties();
    // add alert (min. version)
    String prefix = AlertsPropertiesConfiguration.ALERT_PROP_PREFIX + "1.";
    props.put(prefix + AlertsPropertiesConfiguration.ID_PROP, "ID");
    props.put(prefix + AlertsPropertiesConfiguration.ID_PROP, "ID");
    env.getPropertySources().addFirst(new PropertiesPropertySource("alerts-test", props));
    AlertsPropertiesConfiguration conf = new AlertsPropertiesConfiguration(env);
    conf.initProps();
}