function testProtocol()
 {
     Braintree_Configuration::environment('development');
     $p = Braintree_Configuration::protocol();
     $this->assertEquals('http', $p);
     Braintree_Configuration::environment('sandbox');
     $p = Braintree_Configuration::protocol();
     $this->assertEquals('https', $p);
     Braintree_Configuration::environment('production');
     $p = Braintree_Configuration::protocol();
     $this->assertEquals('https', $p);
     Braintree_Configuration::reset();
 }