public function testInvalidLanguageCode()
 {
     $client = new Client();
     $content = Stream::factory('{"access_token":"123"}');
     $xml = '<ArrayOfstring xmlns="http://schemas.microsoft.com/2003/10/Serialization/Arrays" xmlns:i="http://www.w3.org/2001/XMLSchema-instance"><string></string></ArrayOfstring>';
     $mock = new Mock([new Response(200, [], $content), new Response(200, [], Stream::factory($xml))]);
     $client->getEmitter()->attach($mock);
     $translator = new \badams\MicrosoftTranslator\MicrosoftTranslator($client);
     $translator->setClient('client_id', 'client_secret');
     $languages = $translator->getLanguageNames(['invalid_language']);
     $this->assertTrue(is_array($languages));
     $this->assertTrue(empty($languages));
 }