fix: 셔틀 잔여 시간 정렬 중 null 도착 시각 NPE 방지

src/main/java/in/koreatech/koin/domain/bus/service/shuttle/ShuttleBusService.java

@@ -68,12 +68,12 @@ public ShuttleBusTimetableResponse getShuttleBusTimetable(String id) {
     public List<BusRemainTime> getShuttleBusRemainTimes(BusType busType, BusStation depart, BusStation arrival) {
         List<Route> routes = getShuttleRoutesByBusType(busType);
 
+        // 시간 정렬은 BusService에서 계산할 수 없는 항목을 제외한 뒤 수행한다.
         return routes.stream()
             .filter(route -> route.isRunning(clock))
             .filter(route -> route.isCorrectRoute(depart, arrival, clock))
             .map(route -> route.getRemainTime(depart))
             .distinct()
-            .sorted()
             .toList();
     }
 

src/test/java/in/koreatech/koin/unit/domain/bus/ShuttleBusRemainTimeTest.java

@@ -0,0 +1,169 @@
+package in.koreatech.koin.unit.domain.bus;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.when;
+
+import java.time.Clock;
+import java.time.Instant;
+import java.time.ZoneId;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.EnumSource;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.springframework.beans.BeanUtils;
+import org.springframework.test.util.ReflectionTestUtils;
+
+import in.koreatech.koin.domain.bus.dto.BusRemainTimeResponse;
+import in.koreatech.koin.domain.bus.dto.BusRemainTimeResponse.InnerBusResponse;
+import in.koreatech.koin.domain.bus.enums.BusStation;
+import in.koreatech.koin.domain.bus.enums.BusType;
+import in.koreatech.koin.domain.bus.enums.ShuttleRouteType;
+import in.koreatech.koin.domain.bus.service.BusNoticeRepository;
+import in.koreatech.koin.domain.bus.service.BusService;
+import in.koreatech.koin.domain.bus.service.city.CityBusService;
+import in.koreatech.koin.domain.bus.service.express.ExpressBusService;
+import in.koreatech.koin.domain.bus.service.shuttle.ShuttleBusRepository;
+import in.koreatech.koin.domain.bus.service.shuttle.ShuttleBusService;
+import in.koreatech.koin.domain.bus.service.shuttle.model.ArrivalNode;
+import in.koreatech.koin.domain.bus.service.shuttle.model.Route;
+import in.koreatech.koin.domain.version.model.Version;
+import in.koreatech.koin.domain.version.model.VersionType;
+import in.koreatech.koin.domain.version.service.VersionService;
+
+@ExtendWith(MockitoExtension.class)
+class ShuttleBusRemainTimeTest {
+
+    private static final String SEMESTER = "정규학기";
+    private static final Clock CLOCK = Clock.fixed(
+        Instant.parse("2026-09-05T02:25:00Z"), ZoneId.of("Asia/Seoul"));
+
+    @Mock
+    private ShuttleBusRepository shuttleBusRepository;
+
+    @Mock
+    private VersionService versionService;
+
+    @Mock
+    private BusNoticeRepository busNoticeRepository;
+
+    @Mock
+    private ExpressBusService expressBusService;
+
+    @Mock
+    private CityBusService cityBusService;
+
+    private BusService busService;
+
+    @BeforeEach
+    void setUp() {
+        when(versionService.getVersionEntity(VersionType.SHUTTLE))
+            .thenReturn(Version.builder().title(SEMESTER).build());
+        ShuttleBusService shuttleBusService = new ShuttleBusService(versionService, shuttleBusRepository, CLOCK);
+        busService = new BusService(
+            CLOCK, busNoticeRepository, versionService, List.of(), expressBusService, cityBusService, shuttleBusService);
+    }
+
+    @Test
+    void 토요일_순환버스와_중복_정류장이_있는_주말버스를_함께_조회한다() {
+        // 공개 시간표의 토요일 오후 순환 노선과 하교 3회 구조를 재현한다.
+        Route cycle = route(ShuttleRouteType.SHUTTLE, null,
+            node("한기대", "14:00"), node("2캠퍼스", null), node("터미널", "14:25"),
+            node("천안역", "14:30"), node("한기대", "15:00"));
+        Route weekend = route(ShuttleRouteType.WEEKEND, "하교",
+            node("한기대", "19:10"), node("천안역B", "19:40"), node("터미널", "19:50"),
+            node("두정역", "하차"), node("터미널", null), node("천안역A", null), node("한기대", null));
+        when(shuttleBusRepository.findAllBySemesterTypeAndRouteType(SEMESTER, ShuttleRouteType.SHUTTLE))
+            .thenReturn(List.of(cycle));
+        when(shuttleBusRepository.findAllBySemesterTypeAndRouteType(SEMESTER, ShuttleRouteType.WEEKEND))
+            .thenReturn(List.of(weekend));
+
+        BusRemainTimeResponse response = getRemainTime(BusType.SHUTTLE);
+
+        assertThat(response).isEqualTo(new BusRemainTimeResponse(
+            "shuttle", new InnerBusResponse(null, 10800L), null));
+    }
+
+    @ParameterizedTest
+    @EnumSource(value = BusType.class, names = {"SHUTTLE", "COMMUTING"})
+    void 무효_시간을_제외하고_중복없는_가까운_두_버스를_반환한다(BusType busType) {
+        ShuttleRouteType type = routeType(busType);
+        givenRoutes(busType, List.of(
+            departure(type, "15:00"),
+            duplicateDeparture(type, null),
+            departure(type, "14:25"),
+            duplicateDeparture(type, "정차"),
+            departure(type, "14:25"),
+            departure(type, "16:00"),
+            departure(type, "10:00")
+        ));
+
+        BusRemainTimeResponse response = getRemainTime(busType);
+
+        assertThat(response).isEqualTo(new BusRemainTimeResponse(
+            busType.getName(), new InnerBusResponse(null, 10800L), new InnerBusResponse(null, 12900L)));
+    }
+
+    @ParameterizedTest
+    @EnumSource(value = BusType.class, names = {"SHUTTLE", "COMMUTING"})
+    void 계산할_수_없는_시간과_운행_종료_항목만_있으면_빈_응답을_반환한다(BusType busType) {
+        ShuttleRouteType type = routeType(busType);
+        givenRoutes(busType, List.of(
+            duplicateDeparture(type, null), duplicateDeparture(type, "정차"), departure(type, "10:00")));
+
+        assertThat(getRemainTime(busType)).isEqualTo(new BusRemainTimeResponse(busType.getName(), null, null));
+    }
+
+    @ParameterizedTest
+    @EnumSource(value = BusType.class, names = {"SHUTTLE", "COMMUTING"})
+    void 노선이_없으면_빈_응답을_반환한다(BusType busType) {
+        givenRoutes(busType, List.of());
+
+        assertThat(getRemainTime(busType)).isEqualTo(new BusRemainTimeResponse(busType.getName(), null, null));
+    }
+
+    private BusRemainTimeResponse getRemainTime(BusType busType) {
+        return busService.getBusRemainTime(busType, BusStation.TERMINAL, BusStation.KOREATECH);
+    }
+
+    private void givenRoutes(BusType busType, List<Route> routes) {
+        when(shuttleBusRepository.findAllBySemesterTypeAndRouteType(SEMESTER, routeType(busType)))
+            .thenReturn(routes);
+    }
+
+    private ShuttleRouteType routeType(BusType busType) {
+        return busType == BusType.SHUTTLE ? ShuttleRouteType.SHUTTLE : ShuttleRouteType.WEEKDAYS;
+    }
+
+    private Route departure(ShuttleRouteType type, String time) {
+        return route(type, "등교", node("터미널", time), node("한기대", "도착"));
+    }
+
+    private Route duplicateDeparture(ShuttleRouteType type, String firstTime) {
+        // 노선 판정과 시각 추출의 선택 불일치로 null 시각 객체가 생기는 경계를 재현한다.
+        return route(type, "등교", node("터미널", firstTime), node("터미널", "19:50"), node("한기대", "도착"));
+    }
+
+    private Route route(ShuttleRouteType type, String direction, ArrivalNode... nodes) {
+        Route route = BeanUtils.instantiateClass(Route.class);
+        ReflectionTestUtils.setField(route, "routeName", "테스트 노선");
+        ReflectionTestUtils.setField(route, "routeType", type);
+        ReflectionTestUtils.setField(route, "routeInfo", direction);
+        ReflectionTestUtils.setField(route, "routeDetail", direction);
+        ReflectionTestUtils.setField(route, "runningDays", List.of("SAT"));
+        ReflectionTestUtils.setField(route, "arrivalNodes", new ArrayList<>(List.of(nodes)));
+        return route;
+    }
+
+    private ArrivalNode node(String name, String time) {
+        ArrivalNode node = BeanUtils.instantiateClass(ArrivalNode.class);
+        ReflectionTestUtils.setField(node, "nodeName", name);
+        ReflectionTestUtils.setField(node, "arrivalTime", time);
+        return node;
+    }
+}