Today I learned: Unit testing using Visual Studio Express for Windows Phone

Visual Studio Express 2012 for Windows Phone has built-in support for Unit Testing. Here is the article on MSDN. Here is how to set it up (quickly). VS has to have at least update 2, and all you need to do is to add another project to your solution, choose "Windows Phone Unit Test App". Then write your unit tests and run them using the "TEST" menu on the top bar.

Now if only they allowed access to visualstudio.com for Windows Phone projects or made VS 2013 for Windows Phone available for download.