@BeforeEach
    public void setUp() {
        // Ensure that Openfire caches are reset before each test to avoid tests to affect each-other.
        Arrays.stream(CacheFactory.getAllCaches()).forEach(Map::clear);
        groupManager = GroupManager.getInstance();
    }
Verifies the functionality as implemented by #Group

@author Guus der Kinderen, guus@goodbytes.nl
xmppserver/src/test/java/org/jivesoftware/openfire/group/GroupTest.java