springboot-tdd

# Spring Boot TDD Workflow TDD guidance for Spring Boot services with 80%+ coverage (unit + integration). ## When to Use - New features or endpoints - Bug fixes or refactors - Adding data access logic or security rules ## Workflow 1) Write tests first (they should fail) 2) Implement minimal code to pass 3) Refactor with tests green 4) Enforce coverage (JaCoCo) ## Unit Tests (JUnit 5 + Mockito) ```java @ExtendWith(MockitoExtension.class) class MarketServiceTest { @Mock MarketRepository repo; @InjectMocks MarketService service; @Test void createsMarket() { CreateMarketRequest req = new CreateMarketRequest("name", "desc", Instant.now(), List.of("cat")); when(repo.save(any())).thenAnswer(inv -> inv.getArgument(0)); Market result = service.create(req); assertThat(result.name()).isEqualTo("name"); verify(repo).save(any()); } } ``` Patterns: - Arrange-Act-Assert - Avoid partial mocks; prefer explicit stubbing - Use `@ParameterizedTest` for variants ## Web Layer Tests (MockMvc) ```java @WebMvcTest(MarketController.class) class MarketControllerTest { @Autowired MockMvc mockMvc; @MockBean MarketService marketService; @Test void returnsMarkets() throws Exception { when(marketService.list(any())).thenReturn(Page.empty()); mockMvc.perform(get("/api/markets")) .andExpect(status().isOk()) .andExpect(jsonPath("$.content").isArray()); } } ``` ## Integra...