public void testToCollection() {
   setUpTest();
   one.add("1");
   two.add("2");
   c.addComposited(one, two);
   Collection foo = c.toCollection();
   assertTrue(foo.containsAll(c));
   assertEquals(c.size(), foo.size());
   one.add("3");
   assertTrue(!foo.containsAll(c));
 }