Supertest Express middleware is run after the test

So I created an extention on Express to handle XML, since the application I interface with uses XML still.

const XMLResponseHandler = (
  req: Request,
  res: Response,
  next: NextFunction,
) => {
  res.xml = (body) => res.set('Content-Type', 'application/xml').send(builder.buildObject(body));
  console.log('oogabooga');  //pay attention to this log
  next();
};

declare namespace Express {
  interface Response {
    xml: (body: unknown) => Response;
  }
}

This is the way it's implemented in the controller

const getOrder = async (req: Request, res: Response) => {
  //  seach the db for a resource that matches

  // purely for demonstration purposes
  const order = {
    order: {
      id: '507f191e810c19729de860ea',
      customer: 'John Doe',
    },
  };

  if (req.params.id === '507f191e810c19729de860ea') res.xml(order);
  else res.status(404).send('order not found');
};

This is my test:

describe('user endpoints', () => {
  const consoleTransport = logger.transports.find(
    (transport) => transport.level === 'info',
  );

  let app: Server;
  before(() => {
    app = createApp();
    if (!consoleTransport) return;
    consoleTransport.silent = true;
  });

  after(() => {
    if (!consoleTransport) return;
    consoleTransport.silent = false;
  });

  describe('GET /order/507f191e810c19729de860ea', () => {
    it('returns 200 if the order exists and responds with the order', (done) => {
      request(app)
        .get('/order/507f191e810c19729de860ea')
        .set('Accept', 'application/xml')
        .expect('Content-Type', 'application/xml; charset=utf-8')
        .expect((res: Request) => {
          console.log('---- \n', res.body);
        })
        .expect(200, done);
    });
  });

The res.body in the last console log is an empty object. The console.log('oogabooga') is triggered after the the last console log. Is there a way I can fix these timings?

The log:

---- 
 {}
  //test fails
oogabooga