affaan-m
Test-driven development for Spring Boot using JUnit 5, Mockito, MockMvc, Testcontainers, and JaCoCo. Use when adding features, fixing bugs, or refactoring.
bunx add-skill affaan-m/everything-claude-code -s springboot-tddLoading…
TDD guidance for Spring Boot services with 80%+ coverage (unit + integration).
@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:
@ParameterizedTest for variants@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());
}
}
@SpringBootTest
@AutoConfigureMockMvc
@ActiveProfiles("test")
class MarketIntegrationTest {
@Autowired MockMvc mockMvc;
@Test
void createsMarket() throws Exception {
mockMvc.perform(post("/api/markets")
.contentType(MediaType.APPLICATION_JSON)
.content("""
{"name":"Test","description":"Desc","endDate":"2030-01-01T00:00:00Z","categories":["general"]}
"""))
.andExpect(status().isCreated());
}
}
@DataJpaTest
@AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
@Import(TestContainersConfig.class)
class MarketRepositoryTest {
@Autowired MarketRepository repo;
@Test
void savesAndFinds() {
MarketEntity entity = new MarketEntity();
entity.setName("Test");
repo.save(entity);
Optional<MarketEntity> found = repo.findByName("Test");
assertThat(found).isPresent();
}
}
@DynamicPropertySource to inject JDBC URLs into Spring contextMaven snippet:
<plugin>
<groupId>org.jacoco</groupId>
<artifactId>jacoco-maven-plugin</artifactId>
<version>0.8.14</version>
<executions>
<execution>
<goals><goal>prepare-agent</goal></goals>
</execution>
<execution>
<id>report</id>
<phase>verify</phase>
<goals><goal>report</goal></goals>
</execution>
</executions>
</plugin>
assertThat) for readabilityjsonPathassertThatThrownBy(...)class MarketBuilder {
private String name = "Test";
MarketBuilder withName(String name) { this.name = name; return this; }
Market build() { return new Market(null, name, MarketStatus.ACTIVE); }
}
mvn -T 4 test or mvn verify./gradlew test jacocoTestReportRemember: Keep tests fast, isolated, and deterministic. Test behavior, not implementation details.
Use when you need to run Flow type checking, or when seeing Flow type errors in React code.
Use when you want to validate changes before committing, or when you need to check all React contribution requirements.
Use when feature flag tests fail, flags need updating, understanding @gate pragmas, debugging channel-specific test failures, or adding new flags to React.
Use when you need to check feature flag states, compare channels, or debug why a feature behaves differently across release channels.