Usually, you do not close Windows Store applications. When you stop working with an application, it continues running in the background. The operating system closes it automatically if you have not been working with the application for a while.
When you “launch” an application that is already running, the operating system simply activates the running application instance.
Some applications can store their state. Therefore, after switching, they can be in the state, in which you have left them, but not in their initial state. This may cause issues for your tests.
To avoid problems, we recommend that you close the Windows Store application after the testing process is over.
You can close these applications automatically from tests by using the Process.Close method.
See Also
Testing Windows Store Applications
Deploying Windows Store Tested Applications on Test Computers