Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

JavaScript JavaScript Unit Testing Behavior Driven Development with Mocha & Chai A Testing Test!

JavaScript Unit Testing > Behavior Driven Development with Mocha and Chai > A Testing Test!

This code doesn't work which is straight from the Chai assertion library. Clone.js doesn't work correctly, expected test to fail, but it passed.

clone_spec.js
var expect = require('chai').expect;

describe('clone', function () {
    var clone = require('./clone.js');
    it('some description string', function () {

        expect({foo : 'bar'}).to.deep.equal({foo : 'bar'});

    })
})
clone.js
function clone (objectForCloning) {
    return Object.assign({}, objectForCloning)
}

module.exports = clone

5 Answers

Timothy Schmidt:

Here's one example that I used: "Expect(clone).to.deep.equal({});" clone.js works correctly, specs don’t pass

Timothy Schmidt
Timothy Schmidt
4,806 Points

Ok, I think I know where the misunderstanding is. clone isn't the object you're supposed to test, it's a function that is used to make the clone. You pass an object to the clone function and the result is what you need to test. So, using the example in your last comment, it would be:

expect( clone({}) ).to.deep.equal({});

But, it apparently doesn't work with empty objects, so you need to add a key to the object.

expect( clone({key: "value"}) ).to.deep.equal({key:"value"});

That line passed the exercise for me.

Timothy Schmidt
Timothy Schmidt
4,806 Points

In the code you provided, you're not actually using the clone function.

var expect = require('chai').expect;

describe('clone', function () {
    var clone = require('./clone.js');
    it('some description string', function () {
        // use clone function to clone an object.
        var objClone = clone({ foo : 'bar' });
        expect({foo : 'bar'}).to.deep.equal( objClone );

    })
})

Timothy Schmidt:

I don't understand what you said. The clone function in clone.js is exported & the code challenge question uses it.

Timothy Schmidt
Timothy Schmidt
4,806 Points

The question doesn't use it on it's own. You're meant to use the clone function inside your unit test. So, inside your it function, you need to use clone and then use expect to test that the function provided the correct result.

Timothy Schmidt:

I've tried multiple iterations of "expect(clone).to.deep.equal(objectForCloning);", but nothing passes correctly so I can't complete this code challenge. I've read the Mozilla.org documentation on Object.assign() & also the Chai assertion library. Nothing has hit me to have an "Aha!" moment to realize what the correct answer is. My logic must be faulty.

Timothy Schmidt
Timothy Schmidt
4,806 Points

That's strange. I went to the code challenge before posting to ensure my code worked before posting it. Have you tried using my solution?

If you could comment with one of your examples of using expect(clone).to.deep.equal(objectForCloning);, maybe I can see what's wrong.

Timothy Schmidt:

Thanks! That worked. I don't know what I was doing wrong unless I wasn't including enough () within the (clone()). This quiz question drove me nuts for the last 2 1/2 months! I was mulling over what I read in MDN & what the instructor said about ".deep.equal" in the video. I was going to review it all over again today, but you saved me the effort.