@Test(expected = NoSuchElementException.class)
 public void RemoveTester2() {
   assertNull(dir.remove("Me", "Phone"));
 }
 @Test(expected = NoSuchElementException.class)
 public void RemoveTester3() {
   dir.put("Bob", "Phone", "2");
   assertNull(dir.remove("Me", "Phone"));
 }
 @Test(expected = NoSuchElementException.class)
 public void RemoveTester() {
   dir.put("Horstmann", "Phone", "2");
   dir.remove("Horstmann", "Phone");
   assertNull(dir.get("Horstmann", "Phone"));
 }