How does JUnit 6 interact with Mockito and Spring Test?

// Mockito with JUnit 6:
// Use MockitoExtension (works identically to JUnit 5)
@ExtendWith(MockitoExtension.class)
class OrderServiceTest {

    @Mock
    OrderRepository repository;

    @InjectMocks
    OrderService service;

    @Test
    void createsOrder() {
        when(repository.save(any())).thenReturn(new Order("O-1", Status.PENDING));
        Order order = service.create("item-1", 2);
        assertEquals(Status.PENDING, order.getStatus());
        verify(repository).save(any(Order.class));
    }
}

// Spring Boot Test with JUnit 6:
@SpringBootTest
class ApplicationIntegrationTest {
    // SpringExtension is auto-registered by @SpringBootTest

    @Autowired
    OrderService service;

    @Test
    void contextLoads() {
        assertNotNull(service);
    }
}

// Spring with Mockito beans:
@SpringBootTest
class OrderControllerTest {

    @Autowired MockMvc mockMvc;

    @MockBean              // Spring-managed mock -- replaces real bean in context
    OrderRepository repo;

    @Test
    void getOrders() throws Exception {
        when(repo.findAll()).thenReturn(List.of(new Order("O-1", Status.PENDING)));
        mockMvc.perform(get("/orders"))
               .andExpect(status().isOk())
               .andExpect(jsonPath("$[0].id").value("O-1"));
    }
}

// Dependency versions for JUnit 6 compatibility (mid-2026):
// Mockito 5.x: compatible with JUnit 6
// Spring Boot 3.x: compatible with JUnit 6
// spring-boot-starter-test auto-includes junit-jupiter