Add MP3_RSS_Item test

dir2cast.php

@@ -895,25 +895,28 @@ public function unserialize($serialized)
 
 class MP3_RSS_Item extends Media_RSS_Item 
 {
-    public function getType()
+    public function __construct($filename)
     {
-        return 'audio/mpeg';
+        parent::__construct($filename);
+        $this->setType('audio/mpeg');
     }
 }
 
 class M4A_RSS_Item extends Media_RSS_Item
 {
-    public function getType()
+    public function __construct($filename)
     {
-        return 'audio/mp4';
+        parent::__construct($filename);
+        $this->setType('audio/mp4');
     }
 }
 
 class MP4_RSS_Item extends Media_RSS_Item
 {
-    public function getType()
+    public function __construct($filename)
     {
-        return 'video/mp4';
+        parent::__construct($filename);
+        $this->setType('video/mp4');
     }
 }
 

test/MP3_RSS_ItemTest.php

@@ -0,0 +1,13 @@
+<?php declare(strict_types=1);
+
+use PHPUnit\Framework\TestCase;
+
+class MP3_RSS_ItemTest extends Media_RSS_ItemTest
+{
+    public function getDefaultType()
+    {
+        return 'audio/mpeg';
+    }
+
+    protected $media_rss_item_class = 'MP3_RSS_Item';
+}

test/Media_RSS_ItemTest.php

@@ -50,6 +50,8 @@ public function getID3Comment()
         return '';
     }
 
+    protected $media_rss_item_class = 'Media_RSS_Item';
+
     public function newRSSItem()
     {
         // default tests are conducted with an empty file (which, therefore, has no ID3 tags to read)
@@ -59,7 +61,8 @@ public function newRSSItem()
         $this->mtime = time();
         touch($this->filename, $this->mtime);
 
-        $item = new Media_RSS_Item($this->filename);
+        $class = $this->media_rss_item_class;
+        $item = new $class($this->filename);
         $item->setID3Album($this->getID3Album());
         $item->setID3Title($this->getID3Title());
         $item->setID3Artist($this->getID3Artist());

test/RSS_File_ItemTest.php

@@ -10,6 +10,12 @@ public static function setUpBeforeClass(): void
         RSS_File_Item::$FILES_DIR = getcwd();
     }
 
+
+    public function getDefaultType()
+    {
+        return 'application/octet-stream';
+    }
+
     protected $filename;
     protected $filename_base;
     protected $default_title_from_file;
@@ -44,7 +50,7 @@ public function test_constructor_sets_default_properties_from_filename()
         $this->assertEquals('example.mp3', $item->getFilename());
         $this->assertEquals($this->getDefaultTitle(), $item->getTitle());
         $this->assertEquals('http://www.example.com/mp3/example.mp3', $item->getLink());
-        $this->assertEquals('application/octet-stream', $item->getType());
+        $this->assertEquals($this->getDefaultType(), $item->getType());
     }
 
     public function test_filename_with_full_path()