How to test proximity sensor on Lumia 950

[Inax]

Hi, I'm having problems with my Lumia 950. I got my screen replaced but since then the screen does not turn off during calls, so I guess the proximity sensor was not properly installed. I need to check if the proximity sensor actually works. Is there any app or diagnostic code that allows me to test the proximity sensor? I know there was certain MS software that can do the work, but I don't have a PC nearby.
Thanks.

 

[Rosebank]

App from store, AIDA64, this picks up and lists all the sensors yet proximity is not on the list, there is a light sensor though which I think is the same thing but I may be wrong.
http://forums.windowscentral.com/wi...-any-app-can-test-light-proximity-sensor.html