test : 공지사항 조회 시 정렬 테스트 추가

backend/core/src/test/java/site/timecapsulearchive/core/common/fixture/domain/AnnouncementTestFixture.java

@@ -0,0 +1,22 @@
+package site.timecapsulearchive.core.common.fixture.domain;
+
+import java.time.ZonedDateTime;
+import java.util.ArrayList;
+import java.util.List;
+import site.timecapsulearchive.core.domain.announcement.data.dto.AnnouncementDto;
+
+public class AnnouncementTestFixture {
+
+    public static List<AnnouncementDto> announcementDtos(int size) {
+        List<AnnouncementDto> result = new ArrayList<>();
+        ZonedDateTime now = ZonedDateTime.now();
+        for (int index = 0; index < size; index++) {
+            result.add(
+                new AnnouncementDto("title" + index, "content" + index, String.valueOf(index),
+                    now.plusSeconds(index))
+            );
+        }
+
+        return result;
+    }
+}

backend/core/src/test/java/site/timecapsulearchive/core/domain/announcement/service/AnnouncementServiceTest.java

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+package site.timecapsulearchive.core.domain.announcement.service;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+
+import java.util.Comparator;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+import site.timecapsulearchive.core.common.fixture.domain.AnnouncementTestFixture;
+import site.timecapsulearchive.core.domain.announcement.data.dto.AnnouncementDto;
+import site.timecapsulearchive.core.domain.announcement.repository.AnnouncementRepository;
+
+class AnnouncementServiceTest {
+
+    private final AnnouncementRepository announcementRepository = mock(
+        AnnouncementRepository.class);
+    private final AnnouncementService announcementService = new AnnouncementService(
+        announcementRepository);
+
+    @Test
+    void 공지사항을_조회하면_가장_최근에_생성된_공지사항이_최상단에_위치한다() {
+        //given
+        given(announcementRepository.findAll()).willReturn(AnnouncementTestFixture.announcementDtos(10));
+
+        //when
+        List<AnnouncementDto> announcements = announcementService.findAll();
+
+        //then
+        assertThat(announcements)
+            .isSortedAccordingTo(Comparator.comparing(AnnouncementDto::createdAt).reversed());
+    }
+}