@Test
    public void testSubscriptionRemove() throws Exception
    {
        // Setup test fixture.
        final Roster input = new Roster();
        input.setType(IQ.Type.set);
        final JID address = new JID("foo", "example.org", null);
        final Roster.Subscription subscription = Roster.Subscription.remove;
        input.addItem(address, subscription);

        // Execute system under test.
        final Roster result = IQRosterHandler.ignoreNonRemoveSubscriptionValues(input);

        // Verify results.
        assertTrue(result.getItems().stream().anyMatch(item -> item.getJID().equals(address) && subscription.equals(item.getSubscription())));
    }
Asserts that IQRosterHandler#testIgnoreNonRemoveSubscriptionValues does _not_ remove a subscription attribute of
which the value is 'remove'.
xmppserver/src/test/java/org/jivesoftware/openfire/handler/IQRosterHandlerTest.java