title: Testing Div Sizing Changes
body: <p>I'm trying to find a workable way to set up some jest/enzyme tests for a size watcher component in a react project. </p>
  
  <p>At present I'm watching the <code>clientWidth</code> and <code>clientHeight</code> of a wrapper div to check for sizing changes from the parent. The div itself is styled to fill its parent box with no extraneous border/whitespace i.e., width: 100%, height 100%, margin/padding 0px... etc. </p>
  
  <p>This brings me to my issue. what is a good way to create a mock/wrapper to test this with? I cannot directly alter <code>clientWidth</code> or <code>clientHeight</code> as they are protected, and since I'm using jest/enzyme, modifications to parent css styling do not really "flow" like they do in a browser. I don't really have access to anything like jquery to "cheat" so... any advice on how to create a test scenario for this?</p>