@Test
public void testGetGroups() {

  String user = "user";
  List<String> expResult = Collections.emptyList();
  List<String> result = ngm.getGroups(user);
  assertEquals("No groups should be returned",
      expResult, result);
  ngm.cacheGroupsAdd(Arrays.asList(new String[] {"group1", "group2"}));
  result = ngm.getGroups(user);
  assertEquals("No groups should be returned",
      expResult, result);
  ngm.cacheGroupsRefresh();
  result = ngm.getGroups(user);
  assertEquals("No groups should be returned",
      expResult, result);
}