Express js:middleware function is not invoked

i am trying to implement middle ware function in my express js application it follows a simple MVC architecture.

routes.js under route folder

//load the controller auth.js
var auth = require('../controllers/auth');
//auth route
router.route('/auth').get(auth.simpleAuth);

auth.js under controllers folder

//load the middleware
var middleware = require('../middleware/middleware');

module.exports={
  simpleAuth:function (req,res) {
       //invoke middleware
        middleware.testMiddleware;
        res.send('middleware test completed');
    }
}

middleware.js under middleware folder

module.exports={
    testMiddleware:function (req,res,next) {
        console.log('inside middleware');
        if(req.username == true){
            next();
        }else{
            console.log('auth failed')
        }

    }
}

There is no error message is shown but when i access auth route the middle ware function is not invoked.

via Jabaa