const items = [ { id: 'a' }, { id: 'b' } ]; export default { props: { foo: null, items }, test({ assert, component, target }) { const select = target.querySelector( 'select' ); const options = target.querySelectorAll( 'option' ); assert.equal( options[0].selected, true ); assert.equal( options[0].disabled, true ); assert.equal( options[1].selected, false ); assert.equal( options[1].disabled, false ); // placeholder option value must be blank string for native required field validation assert.equal( options[0].value, '' ); assert.equal( select.checkValidity(), false ); component.foo = items[0]; assert.equal( options[0].selected, false ); assert.equal( options[1].selected, true ); assert.equal( select.checkValidity(), true ); } };