JUnit 5 - Unit Testing

1@ExtendWith(MockitoExtension.class)
2class OrderServiceTest {
3    @Mock
4    private OrderRepository orderRepository;
5 
6    @InjectMocks
7    private OrderService orderService;
8 
9    @Test
10    @DisplayName("Should calculate total with discount")
11    void calculateTotalWithDiscount() {
12        Order order = new Order(100.0, 0.1);
13        when(orderRepository.save(any())).thenReturn(order);
14 
15        double total = orderService.calculateTotal(order);
16 
17        assertThat(total).isEqualTo(90.0);
18        verify(orderRepository).save(order);
19    }
20 
21    @ParameterizedTest
22    @ValueSource(doubles = {0.0, 0.1, 0.5})
23    void validateDiscountRange(double discount) {
24        assertThat(discount).isBetween(0.0, 1.0);
25    }
26}