React testing component prop change with enzyme

Question

I am modifying an example found here:

https://github.com/airbnb/enzyme/blob/master/docs/api/ReactWrapper/setProps.md

class Foo extends React.Component {
    render() {
        return (
            <input className={this.props.name} type="text" value={this.props.name} onChange={()=>{}} />
        );
    }
}

it('should pass and does not', ()=> {
    const wrapper = mount(<Foo name="foo" />);
    expect(wrapper.find('.foo').html()).toBe(`<input class="foo" type="text" value="foo">`);
    wrapper.setProps({ name: 'bar' });
    expect(wrapper.find('.bar').html()).toBe(`<input class="bar" type="text" value="bar">`);
});

Result: Expected '<input class="bar" type="text" value="foo">' to be '<input class="bar" type="text" value="bar">'.

You can see from the result of the test that the className attribute was correctly updated on prop change. But the value of the input remains incorrectly set to 'foo'.

Any ideas on how I can assert that value has been correctly changed on the component receiving new props to a value attribute on an input?

Hawthorne

Answer 1

You have to call a method .update() on a wrapper. (Just after you set new props) This will force update the component and the value of the input should change.

You can read more about it here: http://airbnb.io/enzyme/docs/api/ShallowWrapper/update.html

Rella

Just a note, the OP is using mount, not shallow, so the correct docs should be airbnb.io/enzyme/docs/api/ReactWrapper/update.html ; Another note is that setProp for mount takes a second, callback, argument that executes after the operation has been completed: setProps(someProps, callback) (ref: airbnb.io/enzyme/docs/api/ReactWrapper/setProps.html) – Unproductive