Add Sinon assertions for chai - sinon-chai:
https://github.com/domenic/sinon-chai
Investigate what's going wrong with one test converted sinon-chai format.

To run just the changed test (after doing 'grunt concat' to compose the tests):

./node_modules/.bin/mocha-phantomjs www/tests/index.html?grep="backbone basic authentication"
Merge branch 'testing-enhancements' of github.com:SpiderOak/SpiderOakMobileClient into testing-enhancements