If you don’t have Resharper it’s often handy to be able to run NUnit from within VisualStudio. This is easily achieved from the Tools | External Tools menu. Just point the Command at where you have installed the Nunit executable, and complete the rest of the parameters as follows:
After completing this you should find that you can launch Nunit from the Tools menu using your newly created NUnit 2.6 option 🙂
Convivial Coding 
Great Tip.
You can use Binary dir in the Initial Directory property for test debug and release version.