@Test
 public void deptDirContainsHorstmann() {
   assertNotNull(deptDir.get("Horstmann", "Phone"));
 }
 @Test(expected = NoSuchElementException.class)
 public void RemoveTester() {
   dir.put("Horstmann", "Phone", "2");
   dir.remove("Horstmann", "Phone");
   assertNull(dir.get("Horstmann", "Phone"));
 }