[#54] test: Following 인스턴스 add()에 null 입력시 실패 테스트 작성

src/main/java/com/study/realworld/domain/follow/domain/Followings.java

@@ -1,5 +1,7 @@
 package com.study.realworld.domain.follow.domain;
 
+import com.study.realworld.domain.follow.error.exception.FollowNullPointerException;
+
 import javax.persistence.CascadeType;
 import javax.persistence.Embeddable;
 import javax.persistence.OneToMany;
@@ -17,13 +19,13 @@ public Followings() {
     }
 
     public void addFollowing(final Follow following) {
-        validateArgumentNull(following);
+        validateFollowNull(following);
         followings.add(following);
     }
 
-    private void validateArgumentNull(final Follow following) {
+    private void validateFollowNull(final Follow following) {
         if(Objects.isNull(following)) {
-            throw new IllegalArgumentException();
+            throw new FollowNullPointerException();
         }
     }
 

src/main/java/com/study/realworld/domain/follow/error/exception/FollowBusinessException.java

@@ -0,0 +1,9 @@
+package com.study.realworld.domain.follow.error.exception;
+
+public class FollowBusinessException extends RuntimeException {
+
+    public FollowBusinessException(final String message) {
+        super(message);
+    }
+
+}

src/main/java/com/study/realworld/domain/follow/error/exception/FollowNullPointerException.java

@@ -0,0 +1,11 @@
+package com.study.realworld.domain.follow.error.exception;
+
+public class FollowNullPointerException extends FollowBusinessException {
+
+    private static final String MESSAGE = "Follow 가 null 입니다.";
+
+    public FollowNullPointerException() {
+        super(MESSAGE);
+    }
+
+}

src/test/java/com/study/realworld/domain/follow/domain/FollowingsTest.java

@@ -1,5 +1,6 @@
 package com.study.realworld.domain.follow.domain;
 
+import com.study.realworld.domain.follow.error.exception.FollowNullPointerException;
 import com.study.realworld.domain.user.domain.persist.User;
 import com.study.realworld.domain.user.domain.vo.*;
 import org.junit.jupiter.api.DisplayName;
@@ -13,6 +14,7 @@
 import static com.study.realworld.domain.user.domain.vo.NameTest.USERNAME;
 import static com.study.realworld.domain.user.domain.vo.PasswordTest.PASSWORD;
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.junit.jupiter.api.Assertions.*;
 
 class FollowingsTest {
@@ -30,7 +32,7 @@ void constructor_test() {
 
     @DisplayName("Following 인스턴스 add 테스트")
     @Test
-    void add_fail_test() {
+    void add_test() {
         final Followings followings = new Followings();
         final User user1 = userBuilder(new Email(EMAIL), new Name(USERNAME), new Password(PASSWORD), new Bio(BIO), new Image(IMAGE));
         final User user2 = userBuilder(new Email("email1"), new Name("username1"), new Password("password1"), new Bio("bio1"), new Image("image1"));
@@ -40,4 +42,13 @@ void add_fail_test() {
         assertThat(followings.getFollowings().size()).isEqualTo(1);
     }
 
+    @DisplayName("Following 인스턴스 add()에 null 입력시 실패 테스트")
+    @Test
+    void add_fail_test() {
+        final Followings followings = new Followings();
+        assertThatThrownBy(() -> followings.addFollowing(null))
+                .isInstanceOf(FollowNullPointerException.class)
+                .hasMessage("Follow 가 null 입니다.");
+    }
+
 }