How should I write a unit test forJavaScript frontend service that uses promise with Karma, Mocha and Sinon

Question

Trying to test some services I'm writing that interact with a 3rd party API and wondering how to test it efficiently.

I have the next method:

    function getMemberProfile(memberId) {

        //Make sure memberId is defined and that it is a number
        if (!isNaN(memberId)) {
            return Client.authorizedApiRequest('/members/' + memberId).get();
        }
        return Promise.reject(new Error('Proper memberId was not supplied'));
    }

When Client.authorizedApiRequest('/members/' + memberId).get() calls a 3rd party API and returns a Promise that resolves to some Object (i.e. {id:12,name:'John Doe'}).

So, how should I test the getMemberProfile function? I was thinking about mocking out the Client.authorizedApiRequest("some params").get() with sinon but I can't get it working.

Thanks

Answer 1

OK, got it working. First you'll need to install chai. Then, in your spec file:

beforeEach(function () {
    fakeMember = {
        member: {
            id: 10002,
            first_name: 'John',
            last_name: 'Doe'
        }
    };
});

it('should get a member\'s profile by memberId', function () {

        //mock
        sinon.stub(Client, 'authorizedApiRequest').withArgs('/members/' + fakeMember.member.id).returns({
            get: function () {
                return Promise.resolve(fakeMember);
            }
        });

        return Members.getMemberProfile(fakeMember.member.id).then(function (response) {
            expect(response).to.have.property('member');
            expect(response.member).to.have.property('id', fakeMember.member.id);
            expect(response.member).to.have.property('first_name', fakeMember.member.first_name);
            expect(response.member).to.have.property('last_name', fakeMember.member.last_name);
        });

});