public void testUpdateMemberOfNonExistentGroup() throws Exception {
        final JID needle = new JID("jane@" + Fixtures.XMPP_DOMAIN);
        final DefaultGroupProvider provider = new DefaultGroupProvider();
        provider.createGroup("Test Group A");
        provider.addMember("Test Group A", needle, false);

        assertThrows(GroupNotFoundException.class, () -> provider.updateMember("Test Group B", needle, false));
    }
Verifies that {@link DefaultGroupProvider#updateMember(String, JID, boolean)} throws when trying to update
membership of a non-existent group
xmppserver/src/test/java/org/jivesoftware/openfire/group/DefaultGroupProviderTest.java