diff --git a/src/main/java/com/example/oneul/domain/post/domain/Post.java b/src/main/java/com/example/oneul/domain/post/domain/Post.java
index 44e22a3..719b860 100644
--- a/src/main/java/com/example/oneul/domain/post/domain/Post.java
+++ b/src/main/java/com/example/oneul/domain/post/domain/Post.java
@@ -38,7 +38,7 @@ public class Post implements Serializable {
     @Access(AccessType.PROPERTY)
     @ManyToOne(fetch = FetchType.EAGER, optional = false)
     private UserEntity writer;
-    
+
     public Post() {}
 
     public Post(Long id, LocalDateTime createdAt, LocalDateTime expiredAt, String content, UserEntity writer){
diff --git a/src/main/java/com/example/oneul/domain/post/service/command/PostCommnadServiceImpl.java b/src/main/java/com/example/oneul/domain/post/service/command/PostCommnadServiceImpl.java
index b178f0d..f6595a0 100644
--- a/src/main/java/com/example/oneul/domain/post/service/command/PostCommnadServiceImpl.java
+++ b/src/main/java/com/example/oneul/domain/post/service/command/PostCommnadServiceImpl.java
@@ -36,8 +36,9 @@ public class PostCommnadServiceImpl implements PostCommandService{
         if(userEntity == null){
             throw new ExpiredSessionException("만료된 세션");
         }
+        
         LocalDateTime createdAt = LocalDateTime.now();
-
+        
         Post postEntity =  postCommandRepository.save(
             Post.builder()
                 .content(post.getContent())
@@ -56,7 +57,7 @@ public class PostCommnadServiceImpl implements PostCommandService{
                 postEntity.getWriter().getUsername()
             )
         );
-    
+        
         log.info("user: " + userEntity.toString() + " create " + postEntity.toString());
         return postEntity;
     }
diff --git a/src/main/java/com/example/oneul/infra/dto/PostMessage.java b/src/main/java/com/example/oneul/infra/dto/PostMessage.java
index 5fb2d2e..6e962df 100644
--- a/src/main/java/com/example/oneul/infra/dto/PostMessage.java
+++ b/src/main/java/com/example/oneul/infra/dto/PostMessage.java
@@ -1,6 +1,7 @@
 package com.example.oneul.infra.dto;
 
 import java.time.LocalDateTime;
+import java.util.Objects;
 
 public class PostMessage {
     private String type;
@@ -59,6 +60,23 @@ public class PostMessage {
         this.wirter = writer;
     }
 
+    @Override
+    public boolean equals(Object object){
+        if(this == object) {
+            return true;
+        }
+        if(object == null || getClass() != object.getClass()){
+            return false;
+        }
+        PostMessage that = (PostMessage)object;
+        return this.id == that.id;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(this.id);
+    }
+    
     @Override
     public String toString(){
         return "PostMessage["
diff --git a/src/test/java/com/example/oneul/service/PostCommandSerivceTest.java b/src/test/java/com/example/oneul/service/PostCommandSerivceTest.java
index 4375de3..a3f5689 100644
--- a/src/test/java/com/example/oneul/service/PostCommandSerivceTest.java
+++ b/src/test/java/com/example/oneul/service/PostCommandSerivceTest.java
@@ -1,13 +1,18 @@
 package com.example.oneul.service;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.verify;
 
+import java.time.LocalDateTime;
 import java.util.Optional;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.ArgumentCaptor;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
 import org.springframework.mock.web.MockHttpSession;
@@ -18,6 +23,8 @@ import com.example.oneul.domain.post.dao.command.PostCommandRepository;
 import com.example.oneul.domain.post.domain.Post;
 import com.example.oneul.domain.post.service.command.PostCommandService;
 import com.example.oneul.domain.post.service.command.PostCommnadServiceImpl;
+import com.example.oneul.domain.user.domain.UserEntity;
+import com.example.oneul.infra.dto.PostMessage;
 import com.example.oneul.infra.kafka.KafkaPublisher;
 
 @ActiveProfiles("test")
@@ -27,31 +34,76 @@ public class PostCommandSerivceTest {
     @Mock private PostCommandRepository postCommandRepository;
     @Mock private KafkaPublisher kafkaPublisher;
     protected MockHttpSession httpSession;
+    @Mock private UserEntity mockWriter;
 
     @BeforeEach
     public void setUp() throws Exception {
         postCommandService = new PostCommnadServiceImpl(postCommandRepository, kafkaPublisher);
+        httpSession = new MockHttpSession();
+        httpSession.setAttribute("user", mockWriter);
     }
 
     @Test
     public void createPostTest() throws Exception {
         // given
         Long mockPostId = 1L;
-        Post post = mockPost(mockPostId);
+        Post post = mockPostDTO();
         ReflectionTestUtils.setField(post, "id", mockPostId);
 
         // mocking
-        given(postCommandRepository.save(post)).willReturn(post);
-        given(postCommandRepository.findById(mockPostId)).willReturn(Optional.ofNullable(post));
+        Post createdMockPost = createdMockPost(mockWriter, post.getContent());
+        ReflectionTestUtils.setField(createdMockPost, "id", mockPostId);
+        given(postCommandRepository.save(any())).willReturn(createdMockPost);    
 
         // when
         Post createdPost = postCommandService.createPost(post, httpSession);
 
         // then
         assertEquals(post.getContent(), createdPost.getContent());
+        ArgumentCaptor<PostMessage> captor = ArgumentCaptor.forClass(PostMessage.class);
+        verify(kafkaPublisher).sendMessage(eq("post"), captor.capture());
+        PostMessage postMessage = createPostMessage("INSERT", createdPost);
+        assertEquals(postMessage, captor.getValue());
     }
 
-    private Post mockPost(Long id) {
+    @Test
+    public void updatePostTest() throws Exception {
+        // given
+        Long mockPostId = 1L;
+        Post post = createdMockPost(mockWriter, "unmodified content");
+        ReflectionTestUtils.setField(post, "id", mockPostId);
+        
+        // mocking
+        given(postCommandRepository.findByIdAndWriter(eq(mockPostId), any()))
+                                    .willReturn(Optional.ofNullable(post));
+        ReflectionTestUtils.setField(post, "content", "modified content");
+        given(postCommandRepository.save(post)).willReturn(post);
+
+        // when
+        Post updatedPost = postCommandService.updatePost(mockPostId, post, httpSession);
+
+        // then
+        assertEquals(post.getContent(), updatedPost.getContent());
+        ArgumentCaptor<PostMessage> captor = ArgumentCaptor.forClass(PostMessage.class);
+        verify(kafkaPublisher).sendMessage(eq("post"), captor.capture());
+        PostMessage postMessage = createPostMessage("UPDATE", updatedPost);
+        assertEquals(postMessage, captor.getValue());
+    }
+
+    private PostMessage createPostMessage(String type, Post post) {
+        return new PostMessage(type, post.getId(), post.getCreatedAt(), post.getContent(), null);
+    }
+
+    private Post createdMockPost(UserEntity writer, String content) {
+        LocalDateTime createdAt = LocalDateTime.now();
+        return Post.builder().content(content)
+                            .createdAt(createdAt)
+                            .expiredAt(createdAt.plusHours(24))
+                            .writer(writer)
+                            .build();
+    }
+
+    private Post mockPostDTO() {
         return Post.builder().content("mocking post")
                             .build();
     }