IHF: array_to_xml tests fixed.

Author: dmitry-ivanov

tests/xml/ArrayToXmlTest.php

@@ -39,23 +39,23 @@ public function it_supports_xml_attributes_in_converting()
                     'to' => 'John',
                     'from' => 'Jane',
                     'title' => 'Go to the shop',
-                    '_attributes' => [
+                    '@attributes' => [
                         'priority' => 'low',
                     ],
                 ],
                 1 => [
                     'to' => 'John',
                     'from' => 'Paul',
                     'title' => 'Finish the report',
-                    '_attributes' => [
+                    '@attributes' => [
                         'priority' => 'medium',
                     ],
                 ],
                 2 => [
                     'to' => 'Jane',
                     'from' => 'Jeff',
                     'title' => 'Clean the house',
-                    '_attributes' => [
+                    '@attributes' => [
                         'priority' => 'high',
                     ],
                 ],