UnitTests are now located in tests directory & tiny improvements

tests/Fixtures/Attachment/AttachmentCollection.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace Fixtures\Attachment;
+
+class AttachmentCollection
+{
+    /**
+     * @var Attachment[] $attachments
+     */
+    public $attachments;
+
+    public function __construct(array $attachments = null)
+    {
+        $this->attachments = $attachments;
+    }
+
+    public function hasAttachments()
+    {
+        return $this->attachments !== null && count($this->attachments) > 0;
+    }
+}