Can I run 'Unit Test Library' on Windows Phone 8.1 device via Visual Studio 2015

this is my development environment,

Windows 10
Visual studio 2015 professional 

this is my target,

run unit test on the windows phone 8.1 device

this is my question,

I create empty Unit Test App (Windows Phone) Visual C++ project,

1. I run the default empty test under Debug x86, it works.
2. I changed x86 to ARM and connect with Windows Phone 8.1 device, it doesn't work, and display the message:

   PhoneUnitTestApp1.dll cannot be run. Please create a Windows Store or Windows Phone Unit Test project.

The project I created is Windows Phone Unit Test project, what does this mean, and how do I run unit test in device?