privateメソッドをテストする時メモ

プロダクトコード

GoodsCreateHelper.java

@Slf4j
@Service
@RequiredArgsConstructor
public class GoodsCreateHelper {

    private final GoodsService gService;

    private void create(final GoodsTbl entity) {
        gService.insert(entity);
    }
}

テストコード

GoodsCreateHelperTest.java

@ExtendWith(SpringExtension.class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
@ActiveProfiles(profiles = {"test"})
@TestExecutionListeners({
        DependencyInjectionTestExecutionListener.class,
})
public class GoodsCreateHelperTest {

    @LocalServerPort
    private int port;

    @Autowired
    private GoodsCreateHelper create;

    @Nested
    @DisplayName("createTest")
    class createTest {

        @Test
        void createFail() throws Exception {
            Class<GoodsCreateHelper> clazz = GoodsCreateHelper.class;
            Method method = clazz.getDeclaredMethod("create", GoodsTbl.class);
            method.setAccessible(true);

            GoodsTbl entity = new GoodsTbl();
            InvocationTargetException e = Assertions.assertThrows(InvocationTargetException.class, () -> method.invoke(create, entity));
            Assertions.assertTrue(e.getCause().toString().contains("DataIntegrityViolationException"));
        }
    }
}

肝心なところ

Class<GoodsCreateHelper> clazz = GoodsCreateHelper.class;
Method method = clazz.getDeclaredMethod("create", GoodsTbl.class);
method.setAccessible(true);

GoodsTbl entity = new GoodsTbl();
InvocationTargetException e = Assertions.assertThrows(InvocationTargetException.class, () -> method.invoke(create, entity));

1.リフレクションでメソッド名をハードコーディングで指定している。
2.メソッドへのアクセスを許可する。