test: GenerationService의 테스트 코드 작성 (DASOMBE-16)

Author: junjinyun

src/test/java/dmu/dasom/api/global/generation/GenerationServiceTest.java

@@ -0,0 +1,105 @@
+package dmu.dasom.api.global.generation;
+
+import dmu.dasom.api.domain.common.exception.CustomException;
+import dmu.dasom.api.domain.common.exception.ErrorCode;
+import dmu.dasom.api.global.generation.entity.Generation;
+import dmu.dasom.api.global.generation.repository.GenerationRepository;
+import dmu.dasom.api.global.generation.service.GenerationService;
+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 java.util.Optional;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+@ExtendWith(MockitoExtension.class)
+class GenerationServiceTest {
+
+    @Mock
+    private GenerationRepository generationRepository;
+
+    @InjectMocks
+    private GenerationService generationService;
+
+    @Test
+    @DisplayName("기수 조회 - 저장된 기수 존재")
+    void getCurrentGeneration_success_existing() {
+        // given
+        Generation generation = Generation.builder().generation("36기").build();
+        when(generationRepository.findFirstByOrderByIdDesc()).thenReturn(Optional.of(generation));
+
+        // when
+        String current = generationService.getCurrentGeneration();
+
+        // then
+        assertEquals("36기", current);
+        verify(generationRepository).findFirstByOrderByIdDesc();
+    }
+
+    @Test
+    @DisplayName("기수 조회 - 저장된 기수 없음, 기본값 사용")
+    void getCurrentGeneration_success_default() {
+        // given
+        when(generationRepository.findFirstByOrderByIdDesc()).thenReturn(Optional.empty());
+
+        // when
+        String current = generationService.getCurrentGeneration();
+
+        // then
+        assertEquals("34기", current);
+        verify(generationRepository).findFirstByOrderByIdDesc();
+    }
+
+    @Test
+    @DisplayName("기수 저장 - 신규 생성")
+    void saveOrUpdateGeneration_success_new() {
+        // given
+        String newGenerationValue = "37기";
+        when(generationRepository.findFirstByOrderByIdDesc()).thenReturn(Optional.empty());
+
+        // when
+        generationService.saveOrUpdateGeneration(newGenerationValue);
+
+        // then
+        verify(generationRepository).findFirstByOrderByIdDesc();
+        verify(generationRepository).save(any(Generation.class));
+    }
+
+    @Test
+    @DisplayName("기수 저장 - 기존 값 업데이트")
+    void saveOrUpdateGeneration_success_update() {
+        // given
+        String updatedValue = "38기";
+        Generation existingGeneration = Generation.builder().generation("37기").build();
+        when(generationRepository.findFirstByOrderByIdDesc()).thenReturn(Optional.of(existingGeneration));
+
+        // when
+        generationService.saveOrUpdateGeneration(updatedValue);
+
+        // then
+        assertEquals("38기", existingGeneration.getGeneration());
+        verify(generationRepository).findFirstByOrderByIdDesc();
+        verify(generationRepository).save(existingGeneration);
+    }
+
+    @Test
+    @DisplayName("기수 저장 - 잘못된 형식으로 실패")
+    void saveOrUpdateGeneration_fail_invalidFormat() {
+        // given
+        String invalidValue = "abc123";
+
+        // when
+        CustomException exception = assertThrows(CustomException.class, () -> {
+            generationService.saveOrUpdateGeneration(invalidValue);
+        });
+
+        // then
+        assertEquals(ErrorCode.INVALID_GENERATION_FORMAT, exception.getErrorCode());
+        verifyNoInteractions(generationRepository);
+    }
+}