emberjs/ember.js — pull request #4037 by diogomafra (2014-01-02 00:50:19+00:00)
Title: Failing test for the issue #3994.

I have a problem similar to the issue #3994, but I'm using filterBy and not mapBy.

The error message is:
`TypeError: 'undefined' is not an object (evaluating 'nextArrayOperation.type')`

I created a failing test showing the problem.