Working with Testing

@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
@AutoConfigureMockMvc
class OrderApiIT {
  @Autowired MockMvc mvc;
  @Test void getOrder() throws Exception {
    mvc.perform(get("/api/orders/1"))
       .andExpect(status().isOk())
       .andExpect(jsonPath("$.id").value(1));
  }
}

@WebMvcTest(OrderController.class)
class OrderControllerTests {
  @Autowired MockMvc mvc;
  @MockBean OrderService svc;
  @Test void create() throws Exception {
    when(svc.create(any())).thenReturn(new OrderDto(1L));
    mvc.perform(post("/api/orders").contentType(MediaType.APPLICATION_JSON)
       .content("{\"items\":[]}"))
       .andExpect(status().isCreated());
  }
}

@DataJpaTest
@AutoConfigureTestDatabase(replace = Replace.NONE) // use real DB
class OrderRepositoryTests {
  @Autowired OrderRepository repo;
  @Autowired TestEntityManager em;
  @Test void findsByReference() {
    em.persist(new Order("REF-1"));
    assertThat(repo.findByReference("REF-1")).isPresent();
  }
}

@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
class HttpClientIT {
  @Autowired TestRestTemplate rest;
  @Test void list() {
    ResponseEntity<OrderDto[]> resp = rest.getForEntity("/api/orders", OrderDto[].class);
    assertEquals(HttpStatus.OK, resp.getStatusCode());
  }
}

@SpringBootTest
@Sql(scripts = "/test-data/orders.sql",
     executionPhase = Sql.ExecutionPhase.BEFORE_TEST_METHOD)
@Sql(scripts = "/test-data/cleanup.sql",
     executionPhase = Sql.ExecutionPhase.AFTER_TEST_METHOD)
class OrderTests { /* … */ }

@SpringBootTest
@TestPropertySource(properties = {
  "app.feature.x.enabled=true",
  "spring.datasource.url=jdbc:h2:mem:test"
})
class FeatureXTests { /* … */ }

// Or @SpringBootTest(properties = {...})

@Test
@WithMockUser(username="alice", roles={"ADMIN"})
void adminOnly() throws Exception { /* … */ }

@Test
@WithAnonymousUser
void requiresAuth() throws Exception { /* … */ }

@Test
void jwt() throws Exception {
  mvc.perform(get("/api/me").with(jwt().jwt(j -> j.subject("123"))));
}

@ExtendWith(MockitoExtension.class)
class OrderServiceTests {
  @Mock OrderRepository repo;
  @Mock PaymentClient pay;
  @InjectMocks OrderService service;

  @Test void placesOrder() {
    when(repo.save(any())).thenAnswer(a -> a.getArgument(0));
    Order o = service.place(new NewOrder(/* … */));
    verify(pay).charge(any());
    assertNotNull(o);
  }
}

@SpringBootTest
@Testcontainers
class PostgresIT {
  @Container static PostgreSQLContainer<?> pg = new PostgreSQLContainer<>("postgres:16");
  @DynamicPropertySource
  static void props(DynamicPropertyRegistry r) {
    r.add("spring.datasource.url", pg::getJdbcUrl);
    r.add("spring.datasource.username", pg::getUsername);
    r.add("spring.datasource.password", pg::getPassword);
  }
}
// Or @ServiceConnection (Boot 3.1+)