Set<String> groups;
acl = new AccessControlList(" ");
assertEquals(0, acl.getUsers().size());
assertEquals(0, acl.getGroups().size());
assertEquals(" ", acl.getAclString());
assertEquals(users.size(), 1);
assertEquals(users.iterator().next(), "drwho");
assertEquals("drwho ", acl.getAclString());
assertEquals(groups.size(), 1);
assertEquals(groups.iterator().next(), "tardis");
assertEquals("drwho tardis", acl.getAclString());
assertEquals(users.size(), 2);
Iterator<String> iter = users.iterator();
assertEquals(iter.next(), "drwho");
assertEquals(iter.next(), "joe");
groups = acl.getGroups();
assertEquals(groups.size(), 2);
iter = groups.iterator();
assertEquals(iter.next(), "tardis");
assertEquals(iter.next(), "users");
assertEquals("drwho,joe tardis,users", acl.getAclString());
assertEquals(users.size(), 1);
assertFalse(users.contains("joe"));
groups = acl.getGroups();
assertEquals(groups.size(), 1);