How to test required props in React - unit-testing

Question

I'm trying to write simple test with React and Jest.
Component:
import React from "react";
class Task extends React.Component {
render() {
let onDelete = this.props.onDelete;
return (
<li>
<div className="collapsible-header"><i className="material-icons" onClick={() => onDelete(this.props.taskId)}>delete</i>{this.props.title}</div>
<div className="collapsible-body"><p>{this.props.description}</p></div>
</li>
);
}
};
Task.propTypes = {
title: React.PropTypes.string.isRequired,
taskId: React.PropTypes.number.isRequired,
onDelete: React.PropTypes.func.isRequired,
description: React.PropTypes.string
};
Task.defaultProps = {
description: ''
};
export default Task;
Test
import React from 'react';
import Task from '../src/components/Task';
import renderer from 'react-test-renderer';
test('Task should require properties', () => {
const component = renderer.create( //this will give me React warnings which I would like to assert
<Task></Task>
);
});
Now I would like to assert that title, taskId and onDelete is required for Task component. That I will get React warning about not specifying them (or passing different types).

Answer 1

You can use a spy to find out if any kind of exception was thrown from react. Many people use a library called Sinon.js. From the documentation "A test spy is a function that records arguments, return value, the value of this and exception thrown (if any) for all its calls".
There is a great solution described in more detail here:
How to test React PropTypes through Jest?