public function testErrorHandling()
 {
     try {
         $this->client->checkDomainAvailability(array('DomainName' => 'amazon.com', 'IdnLangCode' => 'zzz'));
         $this->fail('An exception should have been thrown.');
     } catch (ServiceResponseException $e) {
         $this->assertInstanceOf('Aws\\Route53Domains\\Exception\\Route53DomainsException', $e);
         $this->assertEquals('InvalidInput', $e->getExceptionCode());
     }
 }
 /**
  * @covers Aws\Route53Domains\Route53DomainsClient::factory
  */
 public function testFactoryInitializesClient()
 {
     $client = Route53DomainsClient::factory(array('key' => 'foo', 'secret' => 'bar', 'region' => 'us-east-1'));
     $this->assertInstanceOf('Aws\\Common\\Signature\\SignatureV4', $client->getSignature());
     $this->assertInstanceOf('Aws\\Common\\Credentials\\Credentials', $client->getCredentials());
     $this->assertEquals('https://route53domains.us-east-1.amazonaws.com', $client->getBaseUrl());
 }
<?php

session_start();
// if(!empty($_SESSION['user'])){
require 'vendor/autoload.php';
use Aws\Route53Domains\Route53DomainsClient;
//////////////////
require_once '/connectivity/aws_keys.php';
$keys = aws_keys();
$access_key = $keys['access_key'];
$secret_key = $keys['secret_key'];
//////////////////////////
$client = Route53DomainsClient::factory(array('version' => 'latest', 'region' => "us-east-1", 'credentials' => array('key' => $access_key, 'secret' => $secret_key)));
//public function is_domain_available($domain)
//{
$domain_name = $_POST['new_domain'];
$result = $client->checkDomainAvailability(['DomainName' => $_POST['new_domain'], 'IdnLangCode' => '']);
//}
//$result=is_domain_available($_POST['new_domain']);
if (!empty($result)) {
    $result = $result->toArray();
    if (!empty($result)) {
        $_SESSION['rdomain'] = array("status" => $result['Availability'], "domain" => $domain_name);
    }
} else {
    $_SESSION['rdomain'] = array("status" => "Some thing went wrong!", "domain" => $domain_name);
}
header("Location: /aws_r53/domain_home.php");
// }