/** Moo */
 @Test
 public void testContainsTrue() {
   words.add("100");
   assertTrue(words.contains("100"));
   words.add("500");
   assertTrue(words.contains("500"));
 }
 /** Moo */
 @Test
 public void testContainsFalse() {
   assertFalse(words.contains("0"));
   words.add("100");
   assertFalse(words.contains("0"));
   words.add("200");
   assertFalse(words.contains("500"));
 }