I goofed before and added code that was not compatible with Dojo 1.7.  I fixed that.  In doing so, I found two problems.  1) The tests active an editOn editor and then later try to move it.  During the move (done via a DOM appendChild call), the blur event handler was firing and removing the editor from the DOM.  That combo was causing an error in the browser. 2) The editor plug-in module defined variables in which it tracked active editor state.  Because they were defined at the module level, that state was carrying over between tests.