I know about this question (and answers), but despite trying all the suggested options I am still stuck.
I have a solution with multiple projects, but for this parti
Check what version of Visual Studio 2013 you are using. Update 1 has a pretty big issue where it rebuilds everything. See: https://connect.microsoft.com/VisualStudio/feedback/details/811112/unnecessary-solution-rebuild-on-each-test-run
Upgrading to Update 3 did the trick!
I'm not sure if Resharper could affect things as well. I suggest temporarily uninstalling it.