@Test(expected = InvalidValueException.class)
 public void testCantAddMoreThanLimitSugarToInventroy() throws Exception {
   assertEquals(20, CM.checkSugarInventory());
   CM.addSugarInventory(81);
 }
 @Test(expected = InvalidValueException.class)
 public void testCantAddNegativeSugarToInventroy() throws Exception {
   CM.addSugarInventory(-1);
 }