使用SpringBoot编写一个优雅的单元测试

@SpringBootTest
class OrderServiceTests {
    @Autowired
    private OrderRepository orderRepository;
    @Autowired
    private OrderService orderService;
    @Test
    void payOrder() {
        Order order = new Order(1L, false);
        orderRepository.save(order);
        Payment payment = orderService.pay(1L, "4532756279624064");
        assertThat(payment.getOrder().isPaid()).isTrue();
        assertThat(payment.getCreditCardNumber()).isEqualTo("4532756279624064");
    }
}

@Service
public class BookService {
    @Autowired
    private BookRepository repository;
    // ... service methods
}

@Service
public class BookService {
    private BookRepository repository;
    @Autowired
    public BookService(BookRepository repository) {
        this.repository = repository;
    }
}

// 通过mock方法伪造一个orderRepository的实现，这个实现目前什么都不会做
orderRepository = mock(OrderRepository.class);
// 通过mock方法伪造一个paymentRepository的实现，这个实现目前什么都不会做
paymentRepository = mock(PaymentRepository.class)
// 创建一个Order对象以便一会儿使用
Order order = new Order(1L, false);
// 使用when方法，定义当orderRepository.findById(1L)被调用时的行为，直接返回刚刚创建的order对象
when(orderRepository.findById(1L)).thenReturn(Optional.of(order));
// 使用when方法，定义当paymentRepository.save(任何参数)被调用时的行为，直接返回传入的参数。
when(paymentRepository.save(any())).then(returnsFirstArg());

class OrderServiceTests {
    private OrderRepository orderRepository;
    private PaymentRepository paymentRepository;
    private OrderService orderService;
    @BeforeEach
    void setupService() {
        orderRepository = mock(OrderRepository.class);
        paymentRepository = mock(PaymentRepository.class);
        orderService = new OrderService(orderRepository, paymentRepository);
    }
    @Test
    void payOrder() {
        Order order = new Order(1L, false);
        when(orderRepository.findById(1L)).thenReturn(Optional.of(order));
        when(paymentRepository.save(any())).then(returnsFirstArg());
        Payment payment = orderService.pay(1L, "4532756279624064");
        assertThat(payment.getOrder().isPaid()).isTrue();
        assertThat(payment.getCreditCardNumber()).isEqualTo("4532756279624064");
    }
}

@ExtendWith(MockitoExtension.class)
class OrderServiceTests {
    @Mock
    private OrderRepository orderRepository;
    @Mock
    private PaymentRepository paymentRepository;
    @InjectMocks
    private OrderService orderService;
    // ...
}