Q: Why are you generating to playlists and not to test categories for use within the build ?
A: Given the Playlists are a simple xml format, it was easy to generate those. Updating code to facilitate real test categories is currently a harder thing to do. Given test categories work in team build, its still our goal to have that.
Q: Why are you generating a folder structure ?
A: The version of Playlists supported in Visual Studio 2012 Update 2 are simple lists, which can't contain a hierarchy. In order to facilitate this hierarchy, we generate a folder structure.
Q: what is the aggregated.Playlist ?
A: It contains all the tests of the Testlist and its children testlists. Its the same selection if one would select a TestList in the VS2010 interface.