yep it should, but you must be able to specify it, so that you can then check that that node was correctly inserted in the correct place.

So in the test, something like:
```javascript
var mockAttachment = new MockAttachment(xxx);
var renderedNode = document.createElement('div');
mockAttachment.mNextRender = renderedNode;
...
// call stuff on compose
// check that renderedNode is where you think it is
 ```