Edit in JSFiddle

var productBasket = function (products) {
    return {
        total: function () {
            if (!products.length) {
                return 0;
            } else {
                return products[0]
            }
        }
    }
};
 
describe('Product basket', function () {
    describe('#total()', function () {
        it('returns 0 when basket is empty', function () {
            expect(productBasket([]).total()).toEqual(0);
        });
        it('returns price of a single product in the basket', function () {
            expect(productBasket([10]).total()).toEqual(10);
        });
    })
});