function testAuthUrl()
 {
     Braintree_Configuration::environment('development');
     $authUrl = Braintree_Configuration::authUrl();
     $this->assertEquals('http://auth.venmo.dev:9292', $authUrl);
     Braintree_Configuration::environment('qa');
     $authUrl = Braintree_Configuration::authUrl();
     $this->assertEquals('https://auth.qa.venmo.com', $authUrl);
     Braintree_Configuration::environment('sandbox');
     $authUrl = Braintree_Configuration::authUrl();
     $this->assertEquals('https://auth.sandbox.venmo.com', $authUrl);
     Braintree_Configuration::environment('production');
     $authUrl = Braintree_Configuration::authUrl();
     $this->assertEquals('https://auth.venmo.com', $authUrl);
     Braintree_Configuration::reset();
 }