Unable to deploy Windows phone 8.1 (Windows Runtime) app with a unit test project

I've built a Windows Phone 8.1 app (Windows Runtime) and I wanted to create some unit tests for my app.

I have added a Unit Test App to my solution, which actually added a unit test project. I am able to create tests, run, debug and so on. But if I want to deploy the app on the Phone, I get an error stating :

Error: Unable to deploy an x86 package to a Windows Phone device. Change the build configuration to ARM or Neutral or change the Debug Target to an emulator.

I changed the platform target from x86 to AnyCPU project for this test project (on Debug and Release).

Now, I receive the following error :

Error : /platform:anycpu32bitpreferred is not a valid setting for option /target:library or /target:module

I've edited the .csproj file for this Unit Test project and I've removed all the

<Prefer32Bit>true</Prefer32Bit>

for all configurations.

And now, I get the following error :

Error 3 Manifest references file 'vstest_executionengine_platformbridge.dll' which is not part of the payload.

Not sure but, should I just deploy with the test project unloaded? Please let me know - How to handle this properly. Thank you in advance.