case 17: test.complementAll("ab"); break;
case 18: test.complementAll(new UnicodeSet("[ab]")); break;
case 19: test.remove(' '); break;
case 20: test.remove(' ','a'); break;
case 21: test.remove(" "); break;
case 22: test.removeAll(" a"); break;
case 23: test.removeAll(new UnicodeSet("[\\ a]")); break;
case 24: test.retain(' '); break;
case 25: test.retain(' ','a'); break;
case 26: test.retain(" "); break;
case 27: test.retainAll(" a"); break;