Dave Froslie just announced on his blog that the whitepaper "Testing best practices for AX 2012" is now available for download on Microsoft's download center.
It is a good read about ALM (Appliction Lifecycle Management) for AX code both in X++ and Visual Studio, and some guidelines and thoughts on testing, unit testing, gathering requirements, peer reviews, etc.
I've added the whitepaper download to the ALM/TFS page. I will start posting more new AX2012 content soon, including TFS articles. It's overdue. There has been the multi-developer single AOS whitepaper, which I thought was a little disappointing, so I'll make sure to give my thoughts and suggestions on those matters.