public function testFetchLatest10Posts()
 {
     $posts = $this->repository->latest10();
     $this->assertEquals(10, count($posts));
     // 確認是從 100 ~ 91 倒數
     $i = 100;
     foreach ($posts as $post) {
         $this->assertEquals('title ' . $i, $post->title);
         $this->assertEquals('body ' . $i, $post->body);
         $i -= 1;
     }
 }