@Test(expected = InvalidValueException.class)
 public void testCantAddMoreThanLimitCoffeeToInventroy() throws Exception {
   assertEquals(20, CM.checkCoffeeInventory());
   CM.addCoffeeInventory(81);
 }
 @Test(expected = InvalidValueException.class)
 public void testCantAddNegativeCoffeeToInventroy() throws Exception {
   CM.addCoffeeInventory(-1);
 }