How to mock request and response in nodejs to test middleware/controllers?

Question

My application has several layers: middleware, controllers, managers. Controllers interface is identical to middlewares one: (req, res, next).

So my question is: how ca

Answer 1

A bit old post, but I would like to give my 2 cents. The approach you want to take depends on whether you are doing unit testing or integration testing. If you are going down the route of using supertest, that means you are running the actual implementation code and that means you are doing integration testing. If that's what you want to do this approach is fine.

But if you are doing unit testing, you would mock req and res objects (and any other dependencies involved). In the below code (non-relevant code removed for brevity), I am mocking res and giving just a mock implementation of json method, as that's the only method I need for my tests.

// SUT
kids.index = function (req, res) {
if (!req.user || !req.user._id) {
    res.json({
        err: "Invalid request."
    });
} else {
    // non-relevent code
}
};

// Unit test
var req, res, err, sentData;
describe('index', function () {

    beforeEach(function () {
        res = {
            json: function (resp) {
                err = resp.err;
                sentData = resp.kids;
            }
        };
    });
    it("should return error if no user passed in request", function () {
        req = {};

        kidsController.index(req, res);
        expect(err).to.equal("Invalid request.");

    });

    /// More tests....
})