Mock passport.js with an own strategy

passport-mock.js

/**
 * Author: Michael Weibel <michael.weibel@gmail.com>
 * License: MIT
 */

var passport = require('passport')
	, StrategyMock = require('./strategy-mock');

module.exports = function(app, options) {
	// create your verify function on your own -- should do similar things as
	// the "real" one.
	passport.use(new StrategyMock(options, verifyFunction));

	app.get('/mock/login', passport.authenticate('mock'));
};

strategy-mock.js

/**
 * Author: Michael Weibel <michael.weibel@gmail.com>
 * License: MIT
 */
"use strict";

var passport = require('passport')
	, util = require('util');

function StrategyMock(options, verify) {
	this.name = 'mock';
	this.passAuthentication = options.passAuthentication || true;
	this.userId = options.userId || 1;
	this.verify = verify;
}

util.inherits(StrategyMock, passport.Strategy);

StrategyMock.prototype.authenticate = function authenticate(req) {
	if (this.passAuthentication) {
		var user = {
				id: this.userId
			}
			, self = this;
		this.verify(user, function(err, resident) {
			if(err) {
				self.fail(err);
			} else {
				self.success(resident);
			}
		});
	} else {
		this.fail('Unauthorized');
	}
}

module.exports = StrategyMock;

test.js

/**
 * Author: Michael Weibel <michael.weibel@gmail.com>
 * License: MIT
 */
var request = require('supertest')
	, superagent = require('superagent')
	, path = require('path')
	, app = require(path.join(process.cwd(), 'index.js'))()
	, passportMock = require(path.join(process.cwd(), 'src', 'shared', 'test', 'passport-mock'));

describe('GET /protected-resource authorized', function() {
	var agent = superagent.agent();

	beforeEach(function(done) {
		passportMock(app, {
			passAuthentication: true,
			userId: 1
		});
		request(app)
			.get('/mock/login')
			.end(function(err, result) {
				if (!err) {
					agent.saveCookies(result.res);
					done();
				} else {
					done(err);
				}
			});
	})

	it('should allow access to /protected-resource', function(done) {
		var req = request(app).get('/protected-resource');
		agent.attachCookies(req);
		req.expect(200, done);
	});
});

Can you give an example of a verifyFunction implementation?
How would this work if my app is instantiated once at the beginning of all the tests and the app instance isn't available during the test? The issue I see is that I can't pass in app to passportMock() and so I can't register the middleware and route.

You can see an example here:
https://github.com/jaredhanson/passport-local#configure-strategy
And I think verifyFunction for auth success case should be some kind like this:

function verifyFunction (user, done) { // user = { id: 1};
   // Emulate database fetch result
    var mock = {
       id: 1,
       role: User.ROLE_DEFAULT,
       first_name: 'John',
       last_name: 'Doe'
    };
    done(null, mock);
}

For example if we want test an auth fail situations we shoud use:

 function verifyFunction (user, done) {
    done(new Error('Only authenticated'));
 }

Very useful, thanks @mweibel 👍

I'll give some input as well so that others don't waste hours figuring out why after authentication, it gives a 404 on the login url. It is because you must provide a successRedirect so that passport know where to redirect the client once the authentication has pass.

So in passport-mock.js line 14, it should look like that instead:

app.get('/auth/google', passport.authenticate('mock',{successRedirect: '/',failureRedirect: '/login'}));

And thanks to the author for that code, it helps for unit test my app! :)

Thank you for this example, it helped a lot. Otherwise, just wanted to point out that it's always going to pass authentication, regardless of StrategyMock constructor options:
this.passAuthentication = options.passAuthentication || true;