function testPortNumber()
 {
     Braintree_Configuration::environment('development');
     $pn = Braintree_Configuration::portNumber();
     $this->assertEquals(getenv("GATEWAY_PORT") ? getenv("GATEWAY_PORT") : 3000, $pn);
     Braintree_Configuration::environment('sandbox');
     $pn = Braintree_Configuration::portNumber();
     $this->assertEquals(443, $pn);
     Braintree_Configuration::environment('production');
     $pn = Braintree_Configuration::portNumber();
     $this->assertEquals(443, $pn);
     Braintree_Configuration::reset();
 }