test: 좋아요 추가 API 단위 테스트 작성

Author: dnzp75

src/test/java/com/example/log4u/domain/like/service/LikeServiceTest.java

@@ -0,0 +1,98 @@
+package com.example.log4u.domain.like.service;
+
+import static org.assertj.core.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.BDDMockito.*;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import com.example.log4u.domain.diary.entity.Diary;
+import com.example.log4u.domain.diary.service.DiaryService;
+import com.example.log4u.domain.like.dto.request.LikeAddRequestDto;
+import com.example.log4u.domain.like.dto.response.LikeAddResponseDto;
+import com.example.log4u.domain.like.entity.Like;
+import com.example.log4u.domain.like.repository.LikeRepository;
+import com.example.log4u.domain.user.entity.User;
+import com.example.log4u.fixture.DiaryFixture;
+import com.example.log4u.fixture.LikeFixture;
+import com.example.log4u.fixture.UserFixture;
+
+@DisplayName("좋아요 API 단위 테스트")
+@ExtendWith(MockitoExtension.class)
+public class LikeServiceTest {
+
+	@InjectMocks
+	private LikeService likeService;
+
+	@Mock
+	private LikeRepository likeRepository;
+
+	@Mock
+	private DiaryService diaryService;
+
+	@Test
+	@DisplayName("성공 테스트: 사용자가 게시물에 좋아요를 누르면 좋아요가 저장된다")
+	void likeSuccess() {
+		// given
+		User user = UserFixture.createUserFixture();
+		Diary diary = DiaryFixture.createDiaryFixture();
+		LikeAddRequestDto requestDto = new LikeAddRequestDto(diary.getDiaryId());
+
+		Like like = LikeFixture.createLikeFixture(123243L, user.getUserId(), diary.getDiaryId());
+		Long updatedLikeCount = 11L;
+
+		given(likeRepository.existsByUserIdAndDiaryId(user.getUserId(), diary.getDiaryId())).willReturn(false);
+		given(likeRepository.save(any(Like.class))).willReturn(like);
+		given(diaryService.incrementLikeCount(diary.getDiaryId())).willReturn(updatedLikeCount);
+
+		// when
+		LikeAddResponseDto response = likeService.addLike(user.getUserId(), requestDto);
+
+		// then
+		verify(likeRepository).save(any(Like.class));
+		assertThat(response.liked()).isTrue();
+		assertThat(response.likeCount()).isEqualTo(updatedLikeCount);
+	}
+
+	@Test
+	@DisplayName("예외 테스트: 존재하지 않는 다이어리에 좋아요 요청 시 예외가 발생한다")
+	void likeFail_whenDiaryNotFound() {
+		// given
+		Long userId = 1L;
+		Long diaryId = 100L;
+		LikeAddRequestDto requestDto = new LikeAddRequestDto(diaryId);
+
+		given(likeRepository.existsByUserIdAndDiaryId(userId, diaryId)).willReturn(false);
+		given(diaryService.incrementLikeCount(diaryId)).willThrow(new IllegalArgumentException());
+
+		// when & then
+		assertThrows(IllegalArgumentException.class, () -> {
+			likeService.addLike(userId, requestDto);
+		});
+
+		verify(likeRepository).save(any(Like.class));
+	}
+
+	@Test
+	@DisplayName("예외 테스트: 사용자가 이미 좋아요를 누른 다이어리에 또 요청하면 예외가 발생한다")
+	void likeFail_whenAlreadyLiked() {
+		// given
+		Long userId = 1L;
+		Long diaryId = 100L;
+		LikeAddRequestDto requestDto = new LikeAddRequestDto(diaryId);
+
+		given(likeRepository.existsByUserIdAndDiaryId(userId, diaryId)).willReturn(true);
+
+		// when & then
+		assertThrows(IllegalArgumentException.class, () -> {
+			likeService.addLike(userId, requestDto);
+		});
+
+		verify(likeRepository, never()).save(any(Like.class));
+	}
+}