Q:

What does "Load Playlist started" mean in Visual Studio?

When I load my solution into Visual Studio, I get the following in the Output window:
------ Load Playlist started ------
========== Load Playlist finished (0:00:00.0030077) ==========

What does it mean?

A:

Starting with Visual Studio 2012 Update 2 you can create a Playlist in the Test Explorer that consists of a subset of your existing unit tests. (Before VS2012 Update 2 you could only use Traits to sort of group them together.)
A Playlist is essentially needed when you only want to run specific unit tests that make sense in a given logical context which doesn't match your project or class structure. Playlists are then saved in .playlist files.
If you start VS it will try to load any Playlists which outputs the message you posted. In my case VS only shows this message if I have the Test Explorer window open but I don't know if there are other criteria that can trigger the lookup of the Playlists. So if Test Explorer isn't open then I don't get your Load Playlist started message.
After loading the Playlists VS usually tries to discover the actual unit tests and you get something like this message in the Output window:
------ Discover test started ------
========== Discover test finished: 534 found (0:00:01,6890966) ==========

If you haven't used Playlists before you can read more about them here.

