diff --git a/src/main/java/com/ku/covigator/service/CourseService.java b/src/main/java/com/ku/covigator/service/CourseService.java
index c1bdaf9..ad94dfe 100644
--- a/src/main/java/com/ku/covigator/service/CourseService.java
+++ b/src/main/java/com/ku/covigator/service/CourseService.java
@@ -13,7 +13,6 @@
 import com.ku.covigator.repository.CourseRepository;
 import com.ku.covigator.repository.MemberRepository;
 import lombok.RequiredArgsConstructor;
-import org.jetbrains.annotations.NotNull;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Slice;
diff --git a/src/test/java/com/ku/covigator/service/CourseServiceTest.java b/src/test/java/com/ku/covigator/service/CourseServiceTest.java
index 91db578..f3247b0 100644
--- a/src/test/java/com/ku/covigator/service/CourseServiceTest.java
+++ b/src/test/java/com/ku/covigator/service/CourseServiceTest.java
@@ -165,7 +165,7 @@ void findCoursesSortByCreatedAt() {
 
         //then
         assertAll(
-                () -> assertThat(response.courses().size()).isEqualTo(2),
+                () -> assertThat(response.courses()).hasSize(2),
                 () -> assertThat(response.courses())
                         .extracting("courseId")
                         .containsExactly(savedCourse2.getId(), savedCourse.getId()),