fix: 교수 미정 강의를 시간표에 추가할 때 NullPointerException이 발생하는 문제 수정

src/main/java/in/koreatech/koin/domain/timetableV3/dto/response/TakeAllTimetableLectureResponse.java

@@ -110,7 +110,8 @@ public static List<TakeAllTimetableLectureResponse.InnerTimetableLectureResponse
                         lecture.getName(),
                         lecture.getLectureClass(),
                         lecture.getTarget(),
-                        firstNonNull(timetableLecture.getProfessor(),lecture.getProfessor()),
+                        timetableLecture.getProfessor() != null
+                            ? timetableLecture.getProfessor() : lecture.getProfessor(),
                         lecture.getDepartment(),
                         getCourseType(timetableLecture),
                         getGeneralEducationArea(timetableLecture)

src/main/java/in/koreatech/koin/domain/timetableV3/dto/response/TimetableLectureResponseV3.java

@@ -118,7 +118,8 @@ public static List<InnerTimetableLectureResponseV3> from(List<TimetableLecture>
                         lecture.getName(),
                         lecture.getLectureClass(),
                         lecture.getTarget(),
-                        firstNonNull(timetableLecture.getProfessor(),lecture.getProfessor()),
+                        timetableLecture.getProfessor() != null
+                            ? timetableLecture.getProfessor() : lecture.getProfessor(),
                         lecture.getDepartment(),
                         getCourseType(timetableLecture),
                         getGeneralEducationArea(timetableLecture)

src/test/java/in/koreatech/koin/acceptance/domain/TimetableLectureV3ApiTest.java

@@ -1,7 +1,9 @@
 package in.koreatech.koin.acceptance.domain;
 
+import static org.hamcrest.Matchers.nullValue;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
 
 import java.util.List;
@@ -119,6 +121,27 @@ void setup() {
                 """));
     }
 
+    @Test
+    void 교수가_미정인_정규강의를_생성한다() throws Exception {
+        timetableV2Fixture.시간표1(user, semester);
+        lectureFixture.교수_미정_강의(semester.getSemester());
+
+        mockMvc.perform(
+                post("/v3/timetables/lecture/regular")
+                    .header("Authorization", "Bearer " + token)
+                    .content("""
+                        {
+                            "timetable_frame_id": 1,
+                            "lecture_id": 1
+                        }
+                        """)
+                    .contentType(MediaType.APPLICATION_JSON)
+            )
+            .andExpect(status().isOk())
+            .andExpect(jsonPath("$.timetable[0].class_title").value("교수 미정 강의"))
+            .andExpect(jsonPath("$.timetable[0].professor").value(nullValue()));
+    }
+
     @Test
     void 커스텀강의를_생성한다() throws Exception {
         timetableV2Fixture.시간표1(user, semester);

src/test/java/in/koreatech/koin/acceptance/fixture/LectureAcceptanceFixture.java

@@ -75,6 +75,26 @@ public LectureAcceptanceFixture(LectureRepository lectureRepository) {
         );
     }
 
+    public Lecture 교수_미정_강의(String semester) {
+        return lectureRepository.save(
+            Lecture.builder()
+                .code("MEB312")
+                .semester(semester)
+                .name("교수 미정 강의")
+                .grades("3")
+                .lectureClass("01")
+                .regularNumber("30")
+                .department("기계공학부")
+                .target("기공전체")
+                .professor(null)
+                .isEnglish("")
+                .designScore("0")
+                .isElearning("")
+                .classTime("[100, 101, 102, 103]")
+                .build()
+        );
+    }
+
     public Lecture 영어청해(String semester) {
         return lectureRepository.save(
             Lecture.builder()

src/test/java/in/koreatech/koin/unit/domain/timetableV3/dto/response/TimetableLectureProfessorResponseTest.java

@@ -0,0 +1,94 @@
+package in.koreatech.koin.unit.domain.timetableV3.dto.response;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import in.koreatech.koin.domain.timetable.model.Lecture;
+import in.koreatech.koin.domain.timetableV2.model.TimetableLecture;
+import in.koreatech.koin.domain.timetableV3.dto.response.TakeAllTimetableLectureResponse;
+import in.koreatech.koin.domain.timetableV3.dto.response.TimetableLectureResponseV3;
+
+@SuppressWarnings("NonAsciiCharacters")
+class TimetableLectureProfessorResponseTest {
+
+    @Test
+    void 강의와_시간표_강의의_교수가_모두_없어도_교수는_null로_응답한다() {
+        TimetableLecture timetableLecture = timetableLecture(lecture(null), null);
+
+        var response = TimetableLectureResponseV3.InnerTimetableLectureResponseV3
+            .from(List.of(timetableLecture));
+
+        assertThat(response).hasSize(1);
+        assertThat(response.get(0).professor()).isNull();
+    }
+
+    @Test
+    void 시간표_강의의_교수가_없으면_강의의_교수로_응답한다() {
+        TimetableLecture timetableLecture = timetableLecture(lecture("허준기"), null);
+
+        var response = TimetableLectureResponseV3.InnerTimetableLectureResponseV3
+            .from(List.of(timetableLecture));
+
+        assertThat(response.get(0).professor()).isEqualTo("허준기");
+    }
+
+    @Test
+    void 시간표_강의에_교수가_있으면_강의의_교수보다_우선한다() {
+        TimetableLecture timetableLecture = timetableLecture(lecture("허준기"), "수정된 교수");
+
+        var response = TimetableLectureResponseV3.InnerTimetableLectureResponseV3
+            .from(List.of(timetableLecture));
+
+        assertThat(response.get(0).professor()).isEqualTo("수정된 교수");
+    }
+
+    @Test
+    void 이수한_전체_수업_응답도_교수가_모두_없으면_null로_응답한다() {
+        TimetableLecture timetableLecture = timetableLecture(lecture(null), null);
+
+        var response = TakeAllTimetableLectureResponse.InnerTimetableLectureResponseV3
+            .from(List.of(timetableLecture));
+
+        assertThat(response).hasSize(1);
+        assertThat(response.get(0).professor()).isNull();
+    }
+
+    @Test
+    void 이수한_전체_수업_응답은_시간표_강의의_교수가_없으면_강의의_교수로_응답한다() {
+        TimetableLecture timetableLecture = timetableLecture(lecture("허준기"), null);
+
+        var response = TakeAllTimetableLectureResponse.InnerTimetableLectureResponseV3
+            .from(List.of(timetableLecture));
+
+        assertThat(response.get(0).professor()).isEqualTo("허준기");
+    }
+
+    private Lecture lecture(String professor) {
+        return Lecture.builder()
+            .code("MEB311")
+            .semester("20192")
+            .name("재료역학")
+            .grades("3")
+            .lectureClass("01")
+            .regularNumber("35")
+            .department("기계공학부")
+            .target("기공전체")
+            .professor(professor)
+            .isEnglish("")
+            .designScore("0")
+            .isElearning("")
+            .classTime("[100, 101, 102, 103, 308, 309]")
+            .build();
+    }
+
+    private TimetableLecture timetableLecture(Lecture lecture, String professor) {
+        return TimetableLecture.builder()
+            .lecture(lecture)
+            .grades("0")
+            .professor(professor)
+            .build();
+    }
+}