@Test
 public void getAuthorizationHeader() {
   BraintreeGateway config =
       new BraintreeGateway(
           Environment.DEVELOPMENT,
           "development_merchant_id",
           "integration_public_key",
           "integration_private_key");
   assertEquals(
       "Basic aW50ZWdyYXRpb25fcHVibGljX2tleTppbnRlZ3JhdGlvbl9wcml2YXRlX2tleQ==",
       config.getAuthorizationHeader());
 }