This is a continuation of #151, which fixed the skipping of nodes, but the same issue exists for props.

Here's an example to demonstrate the problem:

import React from 'react';
import {shallow} from 'enzyme';

const Box = ({className}) => (
  <div className={className}/>
);

shallow(<Box/>).equals(<div/>); //=> false
shallow(<Box/>).equals(<div className={undefined}/>); //=> true
shallow(<Box className="awesome"/>).equals(<div className="awesome"/>); //=> true

nodeEqual() fails, because it expects className={undefined} property in the other component (<div/>). This is happening here https://github.com/airbnb/enzyme/blob/master/src/Utils.js#L94. Tested using the latest enzyme available on npm (2.5.1).

I think this case should be covered in enzyme by ignoring null and undefined props, which is what React does too. If everyone agrees, I can submit a PR to fix it ;)