unit tests for post service

Author: miliariadnane

src/main/java/dev/nano/springboottesting/service/PostServiceImpl.java

@@ -1,11 +1,14 @@
 package dev.nano.springboottesting.service;
 
 import dev.nano.springboottesting.entity.Post;
+import dev.nano.springboottesting.entity.User;
 import dev.nano.springboottesting.repository.PostRepository;
+import org.springframework.stereotype.Service;
 
 import java.util.List;
 import java.util.Optional;
 
+@Service
 public class PostServiceImpl implements PostService {
 
     private final PostRepository postRepository;
@@ -35,6 +38,9 @@ public Post savePost(Post post) {
 
     @Override
     public void deletePost(long id) {
-        postRepository.deleteById(id);
+        Optional<Post> post = Optional.of(postRepository.findById(id)
+                .orElseThrow(() -> new IllegalArgumentException("Post not found")));
+
+        postRepository.deleteById(post.get().getId());
     }
 }

src/test/java/dev/nano/springboottesting/service/PostServiceTest.java

@@ -0,0 +1,93 @@
+package dev.nano.springboottesting.service;
+
+import dev.nano.springboottesting.entity.Post;
+import dev.nano.springboottesting.repository.PostRepository;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.ArgumentCaptor;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+
+import java.util.Date;
+import java.util.Optional;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.AssertionsForClassTypes.assertThatThrownBy;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+
+@ExtendWith(SpringExtension.class)
+@SpringBootTest
+class PostServiceTest {
+
+    @Autowired
+    private PostService underTest;
+
+    @MockBean
+    private PostRepository postRepository;
+
+    @Test
+    void canGetAllPostsSuccessfully() {
+        // When
+        underTest.findAllPosts();
+        // Then
+        verify(postRepository).findAll();
+    }
+
+    @Test
+    void canCreateNewPostSuccessfully() {
+        // Given
+        Post post = new Post(
+                1L,
+                "Post 1",
+                "This is the description of post 1",
+                new Date(),
+                1
+        );
+        // When
+        underTest.savePost(post);
+        // Then
+        ArgumentCaptor<Post> postArgumentCaptor = ArgumentCaptor.forClass(Post.class);
+        verify(postRepository).save(postArgumentCaptor.capture());
+        Post postReturned = postArgumentCaptor.getValue();
+        assertThat(postReturned).isEqualTo(post);
+    }
+
+    @Test
+    void canDeletePost() {
+        // Given
+        long postId = 1L;
+        Post postMock = new Post(
+                postId,
+                "Post 1",
+                "This is the description of post 1",
+                new Date(),
+                1
+        );
+        given(postRepository.findById(postId)).willReturn(Optional.of(postMock));
+        // When
+        underTest.deletePost(postId);
+        // Then
+        verify(postRepository).deleteById(postId);
+    }
+
+    @Test
+    void willThrowExceptionWhenDeletePostWithInvalidId() {
+        // Given
+        long postId = 1L;
+        given(postRepository.findById(postId)).willReturn(Optional.empty());
+
+        // When
+        // Then
+        assertThatThrownBy(() -> underTest.deletePost(postId))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessageContaining("Post not found");
+
+        verify(postRepository, never()).deleteById(any());
+    }
+
+}