public void testGroupNamesMultiple() throws Exception
    {
        // Setup test fixture.
        final DefaultGroupProvider provider = new DefaultGroupProvider();
        provider.createGroup("Test Group A");
        provider.createGroup("Test Group B");

        // Execute system under test.
        final Collection<String> result = provider.getGroupNames();

        // Verify result.
        assertEquals(2, result.size());
        assertTrue(result.contains("Test Group A"));
        assertTrue(result.contains("Test Group B"));
    }
Verifies that a {@link DefaultGroupProvider#getGroupNames()} returns a collection containing all group name
when multiple groups are present.
xmppserver/src/test/java/org/jivesoftware/openfire/group/DefaultGroupProviderTest.java