Use Agents for Visual Studio 2015 for distributing automated tests across multiple remote machines for continuous testing in Team Build or Release Management pipelines. The agent package can be downloaded, installed, and configured using the ‘Visual Studio Test Agent Deployment’ task from the task catalog. Couple this with the ‘Run Functional Tests’ task for running tests and collecting diagnostic data such as code coverage.

Agents for Visual Studio 2015 cannot be used for load testing, running functional tests in the XAML build workflows, running automated tests using Microsoft Test Manager (MTM) or for managing lab environments using Visual Studio Lab Management.

For these scenarios, please use Agents for Visual Studio 2013 Update 5.

For more details, please refer this page.

To find out what's new in Visual Studio 2015, see the Visual Studio 2015 Release Notes.

For a list of fixed bugs and known issues, see the Visual Studio 2015 KB Article

VS Release Notes
TFS Release Notes
VS Known Issues
System Requirements
Compatibility