### Question:
OrderServiceImpl implements OrderService { @Override public Response modifyOrder(String orderId, int status, HttpHeaders headers) { Order order = orderRepository.findById(UUID.fromString(orderId)); if (order == null) { return new Response<>(0, orderNotFound, null); } else { order.setStatus(status); orderRepository.save(order); return new Response<>(1, "Modify Order Success", order); } }  @Override Response getSoldTickets(Seat seatRequest, HttpHeaders headers); @Override Response findOrderById(UUID id, HttpHeaders headers); @Override Response create(Order order, HttpHeaders headers); @Override Response alterOrder(OrderAlterInfo oai, HttpHeaders headers); @Override Response<ArrayList<Order>> queryOrders(OrderInfo qi, String accountId, HttpHeaders headers); @Override Response queryOrdersForRefresh(OrderInfo qi, String accountId, HttpHeaders headers); List<String> queryForStationId(List<String> ids, HttpHeaders headers); @Override Response saveChanges(Order order, HttpHeaders headers); @Override Response cancelOrder(UUID accountId, UUID orderId, HttpHeaders headers); @Override Response queryAlreadySoldOrders(Date travelDate, String trainNumber, HttpHeaders headers); @Override Response getAllOrders(HttpHeaders headers); @Override Response modifyOrder(String orderId, int status, HttpHeaders headers); @Override Response getOrderPrice(String orderId, HttpHeaders headers); @Override Response payOrder(String orderId, HttpHeaders headers); @Override Response getOrderById(String orderId, HttpHeaders headers); @Override void initOrder(Order order, HttpHeaders headers); @Override Response checkSecurityAboutOrder(Date dateFrom, String accountId, HttpHeaders headers); @Override Response deleteOrder(String orderId, HttpHeaders headers); @Override Response addNewOrder(Order order, HttpHeaders headers); @Override Response updateOrder(Order order, HttpHeaders headers);  }### Answer:
@Test public void testModifyOrder1() { Mockito.when(orderRepository.findById(Mockito.any(UUID.class))).thenReturn(null); Response result = orderServiceImpl.modifyOrder(UUID.randomUUID().toString(), 1, headers); Assert.assertEquals(new Response<>(0, "Order Not Found", null), result); }
@Test public void testModifyOrder2() { Order order = new Order(); Mockito.when(orderRepository.findById(Mockito.any(UUID.class))).thenReturn(order); Mockito.when(orderRepository.save(Mockito.any(Order.class))).thenReturn(null); Response result = orderServiceImpl.modifyOrder(UUID.randomUUID().toString(), 1, headers); Assert.assertEquals("Modify Order Success", result.getMsg()); }