receive_cds_test.js

it('adds the received copies to the stock for that CD', function(){
            const cd = new CD(0, 10, new Description('Bat Out Of Hell', 'Meatloaf'));
            const catalogue = new Catalogue(contents=[cd]);
            const warehouse = new Warehouse(catalogue);
            const batch = {
                cds: [
                    {
                        title: 'Bat Out Of Hell',
                        artist: 'Meatloaf',
                        copies: 10
                    }
                ]
            }
            warehouse.receive(batch);
            assert.equal(cd.stock, 20);
        })