I have several projects hosted in Visual Studio Online (formerly TFS)
For one of my solutions, I created a hosted assembly controller that runs xUnit to run all of my unit tests. This works great, because every time I check my code, continuous integration starts, builds my solution and runs my tests.
This is the popup window of the assembly controller Solution A (from VS2012)

On the Properties page:

nUnit Solution B, , . B, , A, "".
, .