Stub function calls inside a function

Question

I'm writing a web app using nodejs . I have some utils functions which I export and test separately. There is another function though, that calls some of those utils functions that I would like to stub (using sinon ).
From what I've seen so far, I can only stub methods on objects, so how should I design my utilities functions so I can test all of them?

function util1() {
    ...
}

function util2() {
    ...
}

function util3() {
    ...
    util1();
    ...
    util2();
}

export {
    util1,
    util2,
    util3
}

Inside util3 I want to mock (or stub) the calls for util1 and util2 .

Answer 1

You could put util1 and util2 in a separate module and then use some solution or existing module like mock-require https://github.com/boblauer/mock-require .

But perhaps the simplest solution is actually to change your design to use objects. Then you could create your object with stubs and feed it into an object with a util3 method.

Answer 2

One easy way would be to:

function util3() {
    ...
    moddule.exports.util1();
    ...
    module.exports.util2();
}

The second way is to wrap everything in a map

var self = module.exports = {
    util3 : function() { 
       self.util2();
    },
    util2 : function() { },
..}