testing

name	testing
description	Load when writing or modifying tests. Holds the JUnit 5 + Mockito (BDD) + AssertJ base structure and required rules; per-layer strategy, fixtures, and anti-patterns are split into references/.

Testing (daruda)

JUnit 5 + Mockito + AssertJ. Unit tests (@ExtendWith(MockitoExtension.class)) are the default; integration tests (@SpringBootTest) are not used.

Detailed-rule routing

What you are doing	File to read
Per-layer test strategy for service/controller/entity, MockMvc setup	references/layer-strategy.md
Building fixtures, anti-patterns, run commands	references/fixtures.md

Base structure

@ExtendWith(MockitoExtension.class)
class BoardServiceTest {

	@Mock
	private BoardRepository boardRepository;
	@Mock
	private UserRepository userRepository;

	@InjectMocks
	private BoardService boardService;

	private User author;
	private Board board;

	@BeforeEach
	void setUp() {
		author = User.builder()
			.email("[e-mail]")
			.nickname("작성자")
			.positions(Positions.WORKER)
			.build();
		ReflectionTestUtils.setField(author, "id", 1L);

		board = Board.of("제목", "본문", author);
		ReflectionTestUtils.setField(board, "id", 10L);
	}

	@Nested
	@DisplayName("게시글 생성")
	class Create {

		@Test
		@DisplayName("정상 생성")
		void create_success() {
			// given
			given(userRepository.findById(1L)).willReturn(Optional.of(author));
			CreateBoardRequest request = new CreateBoardRequest("제목", "본문", null);

			// when
			CreateBoardResponse result = boardService.createBoard(1L, request);

			// then
			assertThat(result.boardId()).isEqualTo(10L);
			then(boardRepository).should().save(any(Board.class));
		}

		@Test
		@DisplayName("없는 사용자 → NotFoundException")
		void create_userNotFound() {
			// given
			given(userRepository.findById(999L)).willReturn(Optional.empty());
			CreateBoardRequest request = new CreateBoardRequest("제목", "본문", null);

			// when & then
			assertThatThrownBy(() -> boardService.createBoard(999L, request))
				.isInstanceOf(NotFoundException.class);
		}
	}
}

Required rules

Item	Rule
Class name	{target}Test, no access modifier (package-private)
Class @DisplayName	optional. Required (in Korean) on @Nested classes
Method name	{methodName}_{situation} in English snake_case (create_success, create_userNotFound)
Method @DisplayName	required, in Korean. Failure scenarios use the "condition → ExceptionName" form
Grouping	group by target method into @Nested classes
Body	3-part split with // given / // when / // then comments (exception checks use // when & then)
Stubbing	BDDMockito: given(...).willReturn(...), willThrow, willAnswer
Verification	BDDMockito: then(mock).should().method()
Assertion	AssertJ: assertThat(...), assertThatThrownBy(...)
Entity ID	ReflectionTestUtils.setField(entity, "id", 1L)

No mixing: Mockito.when(...).thenReturn(...) / Mockito.verify(...) / JUnit Assertions.assertEquals are not used in new code. They're mixed in existing files, but new tests are unified to BDD + AssertJ.

static import

For readability, use static imports for the following (this codebase's idiom).

import static org.assertj.core.api.Assertions.*;
import static org.mockito.ArgumentMatchers.*;
import static org.mockito.BDDMockito.*;

Scenarios to cover

For each service method, at minimum:

• Happy path (verify return value + side effects)
• Resource not found → NotFoundException
• No permission → ForbiddenException (when there is an owner check)
• Boundary values (page size, cursor, empty list)

Test code is also subject to Checkstyle (checkstyleTest). Follow tab indentation·120 chars·import order.