add bookmark-of property for hackernews posts

lib/XRay/Formats/Hackernews.php

@@ -61,9 +61,13 @@ class Hackernews extends Format {
         'photo' => null,
         'url' => 'https://news.ycombinator.com/user?id='.$data['by']
       ],
-      'published' => $date->format('c')
+      'published' => $date->format('c'),
     );
 
+    if(isset($data['url'])) {
+      $entry['bookmark-of'] = [$data['url']];
+    }
+
     if(isset($data['title'])) {
       $entry['name'] = $data['title'];
     }

tests/HackernewsTest.php

@@ -21,6 +21,22 @@ class HackernewsTest extends PHPUnit\Framework\TestCase
         return $this->client->parse($request, $response);
     }
 
+    public function testBookmark()
+    {
+        $url = 'https://news.ycombinator.com/item?id=27402392';
+        $response = $this->parse(['url' => $url]);
+
+        $body = $response->getContent();
+        $this->assertEquals(200, $response->getStatusCode());
+        $data = json_decode($body, true);
+
+        $this->assertEquals(200, $data['code']);
+        $this->assertEquals('hackernews', $data['source-format']);
+
+        $this->assertEquals(['https://kevincox.ca/2021/06/04/http-range-caching/'], $data['data']['bookmark-of']);
+        $this->assertEquals('The Impossibility of Perfectly Caching HTTP Range Requests', $data['data']['name']);
+    }
+
     public function testSubmission()
     {
         $url = 'https://news.ycombinator.com/item?id=14516538';

tests/data/hacker-news.firebaseio.com/v0_item_27402392.json

@@ -0,0 +1,11 @@
+HTTP/1.1 200 OK
+Server: nginx
+Date: Fri, 09 Jun 2017 14:30:19 GMT
+Content-Type: application/json; charset=utf-8
+Content-Length: 1701
+Connection: keep-alive
+Access-Control-Allow-Origin: *
+Cache-Control: no-cache
+Strict-Transport-Security: max-age=31556926; includeSubDomains; preload
+
+{"by":"giuliomagnifico","descendants":0,"id":27402392,"score":2,"time":1622869705,"title":"The Impossibility of Perfectly Caching HTTP Range Requests","type":"story","url":"https://kevincox.ca/2021/06/04/http-range-caching/"}