@Test
 public void calculateDiscountPoints() {
   String productsFlatFile = "EL-002,FU-007,FU-008";
   Purchase result = null;
   result = BillingCalculator.calculateTotalPurchase(customer, productsFlatFile);
   Customer client = Mockito.mock(Customer.class);
   client = result.getCustomer();
   when(client.calculateDiscountPoints())
       .thenReturn(result.getTotalPrice().multiply(new BigDecimal(Math.random() * 0.02)));
   when(client.discountPoints()).thenReturn(true);
   if ((client.getPoints().intValue()) > 1000) {
     client.discountPoints();
   }
 }