function testConstructWithArrayOfCredentials()
 {
     $config = new Braintree_Configuration(array('environment' => 'sandbox', 'merchantId' => 'sandbox_merchant_id', 'publicKey' => 'sandbox_public_key', 'privateKey' => 'sandbox_private_key'));
     $this->assertEquals('sandbox', $config->getEnvironment());
     $this->assertEquals('sandbox_merchant_id', $config->getMerchantId());
 }