assertEquals(new Integer(0),filtered.next());
assertEquals(new Integer(3),filtered.next());
assertEquals(new Integer(6),filtered.next());
assertEquals(new Integer(9),filtered.next());
assertEquals(new Integer(12),filtered.next());
assertEquals(new Integer(15),filtered.next());
assertEquals(new Integer(18),filtered.next());
assertEquals(new Integer(0),filtered.next());
assertEquals(new Integer(3),filtered.next());
assertEquals(new Integer(6),filtered.next());
assertEquals(new Integer(9),filtered.next());
assertEquals(new Integer(12),filtered.next());
assertEquals(new Integer(15),filtered.next());
assertEquals(new Integer(18),filtered.next());
assertEquals(new Integer(0),filtered.next());
assertEquals(new Integer(0),filtered.previous());
assertEquals(new Integer(0),filtered.next());
assertEquals(new Integer(3),filtered.next());
assertEquals(new Integer(6),filtered.next());
assertEquals(new Integer(6),filtered.previous());
assertEquals(new Integer(3),filtered.previous());
assertEquals(new Integer(3),filtered.next());
assertEquals(new Integer(6),filtered.next());
assertEquals(new Integer(9),filtered.next());
assertEquals(new Integer(12),filtered.next());