[#52] feat: follow 확인 기능 구현 및 테스트

src/main/java/com/study/realworld/user/domain/User.java

@@ -101,6 +101,10 @@ public void login(Password rawPassword, PasswordEncoder passwordEncoder) {
         this.password.matchPassword(rawPassword, passwordEncoder);
     }
 
+    public boolean isFollow(User user) {
+        return followingUsers.contains(user);
+    }
+
     public void followingUser(User user) {
         checkFollowingUser(user);
         followingUsers.add(user);

src/test/java/com/study/realworld/user/domain/UserTest.java

@@ -3,6 +3,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.Mockito.when;
 
 import com.study.realworld.global.exception.BusinessException;
@@ -195,6 +196,30 @@ void unfollowingNotExceptionTest() {
             .withMessageMatching("not follow user exception");
     }
 
+    @Test
+    @DisplayName("follow 여부를 확인할 수 있다.")
+    void isFollowTest() {
+
+        // given
+        User user = User.Builder()
+            .profile(Username.of("username"), null, null)
+            .password(Password.of("password"))
+            .email(Email.of("[email protected]"))
+            .build();
+        User followingUser = User.Builder()
+            .profile(Username.of("followingUser"), null, null)
+            .password(Password.of("password"))
+            .email(Email.of("[email protected]"))
+            .build();
+        user.followingUser(followingUser);
+
+        // when
+        boolean result = user.isFollow(followingUser);
+
+        // then
+        assertTrue(result);
+    }
+
     @Test
     @DisplayName("equals hashCode 테스트")
     void userEqualsHashCodeTest() {