src/test/java/com/example/g8backend/service/PostServiceRecommendTest.java

package com.example.g8backend.service;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.example.g8backend.entity.Post;
import com.example.g8backend.entity.PostView;
import com.example.g8backend.mapper.CommentMapper;
import com.example.g8backend.mapper.PostMapper;
import com.example.g8backend.mapper.PostViewMapper;
import com.example.g8backend.service.impl.PostServiceImpl;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.junit.jupiter.MockitoExtension;
import org.springframework.transaction.annotation.Transactional;

import java.sql.Timestamp;
import java.time.Instant;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import static org.junit.jupiter.api.Assertions.*;
import static org.mockito.ArgumentMatchers.*;
import static org.mockito.Mockito.*;

@ExtendWith(MockitoExtension.class)
@Transactional
public class PostServiceRecommendTest {

    @Mock
    private PostMapper postMapper;

    @Mock
    private PostViewMapper postViewMapper;

    @Mock
    private CommentMapper commentMapper;

    @InjectMocks
    private PostServiceImpl postService;

    private Post mockPost;
    private PostView mockPostView;

    @BeforeEach
    void setUp() {
        // 初始化测试数据
        mockPost = new Post()
                .setPostId(1L)
                .setUserId(100L)
                .setPostTitle("Test Post")
                .setViewCount(50)
                .setCreatedAt(Timestamp.from(Instant.now().minusSeconds(7200)))
                .setHotScore(5.0);

        mockPostView = new PostView()
                .setViewId(1L)
                .setUserId(200L)
                .setPostId(1L)
                .setViewTime(Timestamp.from(Instant.now()).toLocalDateTime());
    }

    @Test
    public void testGetRecommendedPosts_ExcludesViewedPosts() {
        // 模拟用户已浏览的帖子ID
        Long userId = 200L;
        when(postViewMapper.findViewedPostIds(userId))
                .thenReturn(Arrays.asList(1L, 2L));

        // 模拟推荐结果（未浏览的帖子）
        Post recommendedPost = new Post().setPostId(3L).setHotScore(8.0);
        when(postMapper.selectPage(any(Page.class), any(QueryWrapper.class)))
                .thenReturn(new Page<Post>().setRecords(Collections.singletonList(recommendedPost)));

        // 调用推荐接口
        Page<Post> result = postService.getRecommendedPosts(1, 10, userId);

        // 验证结果
        assertEquals(1, result.getRecords().size(), "应返回1条推荐结果");
        assertEquals(3L, result.getRecords().get(0).getPostId(), "推荐结果应为未浏览的帖子ID 3");
        assertFalse(result.getRecords().stream().anyMatch(p -> p.getPostId() == 1L), "结果中不应包含已浏览的帖子ID 1");
    }

    @Test
    public void testGetRecommendedPosts_NoViewedPosts() {
        // 模拟用户未浏览任何帖子
        Long userId = 300L;
        when(postViewMapper.findViewedPostIds(userId))
                .thenReturn(Collections.emptyList());

        // 模拟推荐结果（所有帖子按热度排序）
        Post post1 = new Post().setPostId(1L).setHotScore(7.5);
        Post post2 = new Post().setPostId(2L).setHotScore(9.0);
        when(postMapper.selectPage(any(Page.class), any(QueryWrapper.class)))
                .thenReturn(new Page<Post>().setRecords(Arrays.asList(post2, post1)));

        // 调用推荐接口
        Page<Post> result = postService.getRecommendedPosts(1, 10, userId);

        // 验证结果
        assertEquals(2, result.getRecords().size(), "应返回所有帖子");
        assertEquals(2L, result.getRecords().get(0).getPostId(), "热度更高的帖子应排在前面");
    }

    @Test
    public void testCalculateHotScores_UpdatesHotScoreCorrectly() {
        // 设置存根
        when(postMapper.selectList(any(QueryWrapper.class)))
                .thenReturn(Collections.singletonList(mockPost));
        when(postMapper.selectLikeCount(anyLong())).thenReturn(30L);
        when(commentMapper.selectCountByPostId(anyLong())).thenReturn(20L);
        when(postMapper.batchUpdateHotScore(anyList())).thenReturn(1);

        // 执行并验证
        postService.calculateHotScores();
        double expectedScore = (Math.log(51) * 0.2 + 30 * 0.5 + 20 * 0.3) / Math.pow(4, 1.5);
        assertEquals(expectedScore, mockPost.getHotScore(), 0.01);
        verify(postMapper).batchUpdateHotScore(anyList());
    }

    //--------------------- 测试冷启动逻辑 ---------------------
    @Test
    public void testCreatePost_SetsInitialHotScore() {
        Post newPost = new Post().setPostId(4L).setPostTitle("New Post");
        postService.createPost(newPost);

        assertEquals(5.0, newPost.getHotScore(), "新帖子的初始热度应为5.0");
        assertNotNull(newPost.getCreatedAt(), "创建时间不应为空");
    }
    @Test
    public void testConcurrentViewCountUpdate() {
        // 设置存根
        doNothing().when(postMapper).incrementViewCount(anyLong());

        postService.recordViewHistory(100L, 1L);
        postService.recordViewHistory(200L, 1L);

        verify(postMapper, times(2)).incrementViewCount(1L);
        verify(postViewMapper, times(2)).insert(any(PostView.class));
    }
}