const items = [ { id: 'a' }, { id: 'b' } ]; export default { skip_if_ssr: true, props: { foo: 'b', items }, test({ assert, component, target }) { const options = target.querySelectorAll( 'option' ); assert.equal( options[0].selected, false ); assert.equal( options[1].selected, true ); component.foo = items[0].id; assert.equal( options[0].selected, true ); assert.equal( options[1].selected, false ); } };