How to test express middleware that depends on other vendor middleware? - node.js

Question

I wanna test a middleware function that inside calls a vendor middleware function. The middleware is:
const expressJwt = require('express-jwt');
const validateJwt = expressJwt({ secret: 'whatever' });
exports.isAuthenticated = (req, res, next) => {
if (req.query && req.query.hasOwnProperty('access_token')) {
req.headers.authorization = `Bearer ${req.query.access_token}`;
}
validateJwt(req, res, next);
};
I've tried to create a sinon.spy() object and pass it as next parameter, but is not called apparently.
Another approach I've tried is to check if exists req.user, since the purpose of the express-jwt middleware is to validate and attach user to the req object. No luck with this neither.
I've seen the existence of chai-connect, but not sure how to use it.
Any ideas? Highly appreciate it!

Answer 1

I finally managed to do it with proxyquire and chai-connect:
In your mocha config:
chai.use(require('chai-connect-middleware'));
global.connect = chai.connect;
In your test:
describe('isAuthenticated', () => {
// Wrap call to chai.connect into a function to use params and return a Promise
const mockedMiddleware = (changeSecret) => {
let oldToken;
if (changeSecret) {
oldToken = acessToken;
acessToken = 'blabalblalba';
}
return new Promise((resolve, reject) => {
connect.use(middleware.isAuthenticated)
.req(req => {
req.query = { access_token: acessToken };
})
.next((res) => {
acessToken = oldToken;
if (res && res.status === 401) {
reject(res.message);
} else {
resolve();
}
})
.dispatch();
});
};
it('should validate correctly', () =>
mockedMiddleware().should.be.fulfilled
);
it('should not validate', () =>
mockedMiddleware(true).should.be.rejected
);
});