Plupload integration testing

I'm using plupload (version 3) and I'm doing an integration testing. I'd like to add a file to the plupload queue programatically and observe what happens if various forbidden files are added (file too large, wrong mimetype etc).

There is an addFile method, but this only accepts moxie object and I'm not sure how can I mock this object.

Has anyone done it? How else would you suggest testing this?