affaan-m/ecc

springboot-tdd

Test-driven development for Spring Boot using JUnit 5, Mockito, MockMvc, Testcontainers, and JaCoCo.

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How to use

  1. Copy the installation command and review the source package before installing it in your own agent environment.
  2. Check the source document for required tools, credentials and supported hosts.
  3. Describe your input and desired deliverable; review the output against the source material.
npx skills add https://github.com/affaan-m/ecc --skill springboot-tdd

Before you start

  • Installation does not include a model subscription, API allowance or permission to access your files.
  • Repository stars and installation counts describe activity, not an independent quality or security test.
Original skill document

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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());
  }
}

Integration Tests (SpringBootTest)

java
@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());
  }
}

Persistence Tests (DataJpaTest)

java
@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();
  }
}

Testcontainers

  • Use reusable containers for Postgres/Redis to mirror production
  • Wire via @DynamicPropertySource to inject JDBC URLs into Spring context

Coverage (JaCoCo)

Maven snippet:

xml
<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>

Assertions

  • Prefer AssertJ (assertThat) for readability
  • For JSON responses, use jsonPath
  • For exceptions: assertThatThrownBy(...)

Test Data Builders

java
class MarketBuilder {
  private String name = "Test";
  MarketBuilder withName(String name) { this.name = name; return this; }
  Market build() { return new Market(null, name, MarketStatus.ACTIVE); }
}

CI Commands

  • Maven: mvn -T 4 test or mvn verify
  • Gradle: ./gradlew test jacocoTestReport

Remember: Keep tests fast, isolated, and deterministic. Test behavior, not implementation details.

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