@After
  public void tearDown() {
    if (internalDistributedSystem != null) {
      internalDistributedSystem.disconnect();
    }
  }
Integration tests for adding and removing {@code Alert} listeners.
geode-log4j/src/integrationTest/java/org/apache/geode/alerting/log4j/internal/impl/AlertListenerRegistrationIntegrationTest.java