public void test_contains_null() {
   ExternalIdSearch test = ExternalIdSearch.of(_id11, _id12);
   assertEquals(false, test.contains(null));
 }
 // -------------------------------------------------------------------------
 public void test_contains() {
   ExternalIdSearch test = ExternalIdSearch.of(_id11, _id12);
   assertEquals(true, test.contains(_id11));
   assertEquals(true, test.contains(_id11));
   assertEquals(false, test.contains(_id21));
 }