Single test problem for Firefox Mocha testing

[brettz9]

There is one issue in running the Mocha tests for Firefox. (It is some kind of Sinon interaction problem which I reported at sinonjs/sinon#1066 but we need to come up with a test case.)

Firefox has some getStackFrames error with the following specific test: http://localhost:9999/tests-mocha/index.html?grep=IDBTransaction%20events%20should%20fire%20the%20onerror%20event%20if%20an%20asynchronous%20error%20occurs

The test group of which it is a part is http://localhost:9999/tests-mocha/index.html?grep=IDBTransaction%20events

[brettz9]

The mentioned bug seems to have been fix, and it appears to be just a bug remaining with this issue in Firefox, so closing.