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Step 07 — Testing: unit + Testcontainers¶

Obiettivo: una piramide di test sana.

Strategia¶

Livello	Tecnologia	Velocità	Cosa testa
Domain unit	JUnit + AssertJ	<50 ms	Regole intrinseche (state machine, validation)
Service unit	Mockito + JUnit	<100 ms	Logica con repository mockato
Slice test	`@WebMvcTest`, `@DataJpaTest`	<2 s	Layer isolato + Spring context minimo
Integration	Testcontainers + Spring Boot Test	5–15 s	Sistema reale con PostgreSQL effimero

Unit test (dominio)¶

TaskStatusTest.java

@ParameterizedTest
@CsvSource({
        "TODO, IN_PROGRESS, true",
        "TODO, DONE, true",
        "DONE, IN_PROGRESS, false"
})
void transitionsRespectStateMachine(TaskStatus from, TaskStatus to, boolean allowed) {
    assertThat(from.canTransitionTo(to)).isEqualTo(allowed);
}

Service unit con Mockito¶

ProjectServiceTest.java

@ExtendWith(MockitoExtension.class)
class ProjectServiceTest {

    @Mock ProjectRepository repository;
    ProjectMapper mapper = new ProjectMapper();
    ProjectService service;

    @BeforeEach
    void setUp() { service = new ProjectService(repository, mapper); }

    @Test
    void getThrowsWhenMissing() {
        UUID id = UUID.randomUUID();
        when(repository.findById(id)).thenReturn(Optional.empty());

        assertThatThrownBy(() -> service.get(id))
                .isInstanceOf(ResourceNotFoundException.class);
    }
}

Integration test con Testcontainers¶

AbstractIntegrationTest.java

@SpringBootTest(webEnvironment = RANDOM_PORT)
@ActiveProfiles("test")
@Testcontainers
public abstract class AbstractIntegrationTest {

    @Container
    @ServiceConnection                                       // (1)
    static final PostgreSQLContainer<?> POSTGRES =
        new PostgreSQLContainer<>("postgres:16-alpine")
            .withReuse(true);
}

@ServiceConnection (Spring Boot 3.1+) — niente proprietà manuali, Spring legge l'URL del container.

ProjectControllerIT.java (estratto)

@AutoConfigureMockMvc
class ProjectControllerIT extends AbstractIntegrationTest {

    @Autowired MockMvc mockMvc;

    @Test
    void createListGetArchiveAndDelete() throws Exception {
        mockMvc.perform(post("/api/v1/projects")
                .contentType(APPLICATION_JSON)
                .content("{\"name\":\"API redesign\"}"))
            .andExpect(status().isCreated())
            .andExpect(header().exists("Location"));
    }
}

Perché PostgreSQL reale e non H2¶

Problema	H2	Testcontainers (Postgres)
SQL dialect	diverso da prod	identico a prod
Tipi (UUID, jsonb, …)	finti / mancanti	nativi
Migration Flyway	spesso falliscono	OK
Reproducibility	"funziona su H2 ma non in prod"	"se passa qui, passa in prod"

Esercizi¶

Aggiungi un test che verifica version (optimistic lock) incrementarsi a ogni update.
Estrai una Fixtures factory class per costruire Project e Task di test.
Configura testcontainers.reuse.enable=true in ~/.testcontainers.properties e misura lo speedup.

Riferimenti nel codice¶