Execute Unit Test Methods Of Different Project In A Solution

I am working on a web application (.Net 4.5, C#) with Visual Studio 2012. I have multiple project as separate components so each project has its own test project. Now I want to execute all Test projects in a single solution. I have started it and added all test projects in single solution, and executed, it works. But now If in any project, there is any change happened so I need to update dll manually by Adding Reference. Is there any option to update dll in some particular location whenever it builds.

Thanks, VD